Answer:
A plausible hypothesis is that deleterious germline mutations in sperm cells are removed by natural selection since sperms have to compete to fertilize the egg
Explanation:
Sperm cells need to travel through the cervix in order to reach the uterus and fertilize the egg. During this process (which is called 'fertilization'), approximately 300 million sperm cells have to compete in a race to reach an egg. During fertilization, the majority of sperm cells die off quickly because male germinal cells carry mutations that lead to abnormalities (e.g., many sperms have double heads, others no tail, etc). The sperm cells are considered to be physiologically weak because their normal functions can be easily disrupted by mutations and, simultaneously, they are under strong selective pressure to be selected during the sperm race. In consequence, deleterious germline male mutations are expected to be eliminated by natural selection, thereby sperms are selected before fertilization so only the strongest ones can compete in the race to fuse with the egg cell and thus develop one zygote.
Based on the information in the graph, what is the best conclusion to draw
about Africa?
World Population Growth
20,000
10,000
World
5,000
Asia
2,000
Africa
1,000
Europe
WANIA
500
200
100
United States,
Canada, and Greenland
Mexico,
Central America, Caribbean Islands,
and South America
Oceania (Australia and
nearby islands in the Pacific)
50
20
10
1950
1960
1970
A. The fertility rate is very low.
1980
1990
2000
2010
2020
2030
2040
2050
B. It has reached its carrying capacity.
C. The birthrate is higher than the death rate.
oc
D. It has few resources.
The correct answer is C. The birthrate is higher than the death rate.
Explanation
The graph is about the growth of the world population, this shows the population growth of the world, Asia, Africa, Europe, United States, Canada and Greenland, Mexico, Central America, Caribbean Islands, and South America, and Oceania (Australia and nearby islands in the Pacific). This graph covers the time from 1950 to 2050 divided into decades. In the specific case of Africa in 1950 it had a population of close to 300 million people. Subsequently, in 2010 the population of Africa was close to 1 billion people and the projection for the year 2050 is 2 billion people. According to this, it can be concluded that the birth rate is higher than the death rate because the population has a growth trend, which indicates that more people are born than die.
What happens during S phase?
O A. Chromosomes are duplicated.
O B. DNA separates into two nuclei.
O C. The cell splits in two.
O D. Cytoplasm is manufactured.
Answer: A. Chromosomes are duplicated.
Explanation: This is the correct answer on the quiz.
Chromosomes are duplicated in S phase. Therefore, option (A) is correct.
What do you mean by S phase?
Between G1 phase and G2 phase, DNA replication takes place during S phase of the cell cycle. The processes that take place during S-phase are tightly controlled and highly conserved.
The cell replicates its genetic material entirely during the S phase of DNA synthesis; At the end of S phase, a normal diploid somatic cell with a DNA complement of 2N acquires a DNA complement of 4N.
DNA synthesis or replication occurs during the S phase of the cell cycle, which occurs prior to the interphase. Before entering mitosis or meiosis, the cell's genetic material is replicated in this manner, leaving enough DNA for daughter cells to divide.
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omplete the passage to describe the function of the heart.
The pumping of the heart involves the alternate contraction and relaxation of the chambers of the heart. The upper chambers of the heart are called
, and the lower chambers of the heart are called
.
Answer:
The pumping of the heart involves the alternate contraction and relaxation of the chambers of the heart. The upper chambers of the heart are called at atria and the lower chambers of the heart are called ventricles.
a person has a cardiac output of 4.9L per minute. the stroke volume of each heart beat is 70 ML
that's true
stroke volume is the volume of blood pumped by each ventricle per beat
cardiac output is the blood pumped by ventricles per minute
Name two organs that are made up of all four tissues?
Heart and lungs are the two organs that are made up of all four tissues. secretion, movement, strength, excretion and communication are the main functions of tissues.
What are tissues in human body?Tissues are the same type of group of cells which have the same structure and functions together in a unit. Connective tissue, epithelial tissue, muscular tissue, and nerve tissue are the four fundamental forms of tissue. Other tissues are held together and supported by connective tissue bone, blood, and lymph tissues.
All body surfaces are covered in epithelial tissues, which also line bodily cavities and hollow organs and make up the majority of glandular tissue. Connective tissues are presents in the blood cells in the human body. Loose connective tissue, adipose tissue, dense fibrous connective tissue, elastic connective tissue, cartilage, osseous tissue, and blood are further more tissues in the body.
Thus, Heart and lungs are the two organs that are made up of all four tissues.
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Why there is a variation of weather in two different parts of India, though climate
was summer?
Answer:
Due to distance from the equator.
Explanation:
There is a variation of weather in two different parts of India, though climate was summer because both parts experience different amount of sunlight. There are some regions in India which is located on the equator so they experience very hot weather while on the other hand, some regions are present at a large distance from the equator so direct sunlight does not occur and the temperature is moderately warm.
help needed asap please :(
Answer: its the top one
Whch part of reproductive system produces semen
What is the best way to test a hypothesis?
Group of answer choices
design and perform an experiment
create a large spreadsheet with all your data on it
do lots of research
ask scientists, then make an educated guess
Designing and performing an experiment is the best way to test a hypothesis.
What is a Hypothesis?This is defined as a proposed explanation about a particular phenomenon or occurrence.
Performing experiments helps to test if the hypothesis if it is valid or not which is why option A was chosen.
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Describe an equation which is the summary of the process by which a mesophlly cell gives out oxygen.
Answer:
An equation is math so i dont really know
Explanation:
Dude im sorry im just trying get some racks
Question 23 of 32
The diagram below represents the time a cell spends in the two main phases
of the cell cycle. In which phase does a cell spend more time?
O A. Meiosis
B. Prophase
C. Interphase
O D. Mitosis
Interphase is the answer to your question
girl is that mold on your screen?
PLEASE NEED HELP ASAP!!! What statement is true about energy and matter in stars? Select the correct answers.
A. Some matter is converted into energy within stars.
B. Energy in stars causes the fusion of light elements.
C. All energy is converted into matter in stars.
D. Energy and matter are both conserved in stars.
E. Only energy is conserved within stars.
F. Only matter is conserved within stars.
Answer:
I think the answer is A
Explanation:
I would wait for someone else to answer though.
ASAP A group of specialized cells working together to perform a function is a(n) ____________.
A. Tissue
B. Cell
C. Organ
D. Organ system
Answer:
THE answer is gonna be A.Tissue
This is the Answer for your question :-)
I hope you are having a great day :-)
Cross-contamination of food occurs when a. perishable foods are kept at room temperature for more than 2 hours b. a utensil contaminated with a microorganism from a previously handled food contacts a second food c. two or more food handlers work on the same food d. two or more microorganisms grow in the same food
ANSWER: B
explanation: from what I learned in culinary arts, this is kind of a trick question. Its not asking how foods can get contaminated, its asking how CROSS CONTAMINATION can occur. Cross contamination occurs in three ways think of it like this: food-to-food, equipment-to-food, and people-to-food. The answer has to be between B and C. But the answer is B, because the utensil is already contaminated and it is coming in contact with another food. The two or more food handlers working on the same food are not bringing anything contaminated into the situation. Unless they are contaminated (by they I mean their hands lol) then it cross contaminates but that's not it lol im 99% sure the answer Is B.
Cross-contamination of food occurs when two or more foods come into contact with each other, transferring microorganisms from one food to another. This can happen in a number of ways, including direct contact, contact with a contaminated surface or utensil, contact with a contaminated food handler, or contact with airborne microorganisms.
What is the most common type of cross-contamination ?The most common type of cross-contamination is direct contact, which can occur when one food touches another. This is especially true of perishable foods, which should not be kept at room temperature for more than two hours.
If they are kept at room temperature longer than this, bacteria and other microorganisms can quickly multiply, potentially leading to cross-contamination.
Another common way for cross-contamination to occur is through contact with a contaminated surface or utensil. If a utensil that has been used to handle a food contaminated with microorganisms comes into contact with a second food, the microorganisms can transfer to the second food and cause cross-contamination.
Similarly, if two or more food handlers work on the same food, their hands can transfer microorganisms from one food to another, leading to cross-contamination. Finally, if two or more microorganisms grow in the same food, they can interact with each other and potentially cause cross-contamination.
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Why is a control group important in a scientific experiment?
Group of answer choices
It gives the scientist control over WHEN to change variables.
It is a comparison to the group where variables are changing.
It gives the scientist control over WHICH variables to change during the experiment.
It is the group where variables are changing so it controls the results of the experiment.
Explanation:
because it allows you to eliminate or isolate variable/ it allows the experiment to minimize the changes in all the variables except the one being test.
I'm not gonna choose bc I'm not 100% sure either so read what's above, think it over and choose wisely
hope I helped a little and good luck :)
This organ stores the main metal ion that forms part
of the red blood cell. Which ion is this, and what
molecule is it a part of inside the red blood cell?
Answer:
a. Iron (Fe) ion
b. Haemoglobin
Explanation:
Red blood cells (RBC), also known as erythrocytes, are one of the cells found in the blood. Red blood cells are the major components of the blood involved with the transport of oxygen throughout the body. Red blood cells are able to do this because they contain proteinous molecules called HAEMOGLOBIN.
Haemoglobin is a molecule that contains hemic iron groups. Haemoglobin is composed of an IRON ION at the core of its structure, which binds to oxygen atom. Hence, according to this question, haemoglobin is a proteinous molecule that contains iron-binding heme groups in the red blood cells.
What happens if a cell goes through metastasis?
Answer:
In metastasis, cancer cells break away from where they first formed (primary cancer), travel through the blood or lymph system, and form new tumors (metastatic tumors) in other parts of the body. The metastatic tumor is the same type of cancer as the primary tumor.
Metallic bonds are responsible for many properties of metals, such as conductivity. Why is this possible? (1 point)
O Metals have low electronegativity, so they are conductive because they pass charges easily.
OTwo metals bonded together are going to be more conductive than a metal bonded with a nonmetal.
O The bonds can shift because valence electrons are held loosely and move freely.
O An attraction between a positive charge and a negative charge is created.
The correct answer is; Metals have low electronegativity, so they are conductive because they pass charges easily.
Metals are found towards the left hand side in the periodic table. They are known for their low electronegativity. Metals are electropositive. This means that they loose charges(electrons) easily.
A metallic bond is comprised of positively charged metallic ions and a sea of electrons.These electrons can move freely.
This sea of electrons are the charges that are responsible for the properties of metals such as high conductivity.
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Describe the life cycle
of mosquito and cockroach
Answer:
the cockroach life cycle is comprised of three developmental phases, the egg, nymph and the adult stage. Most cockroaches are oviparous — their young grow in eggs outside of the mother's body. ... These nymphs will feed and go through a series of moultings over a period of one year as they develop into adults
The description of life cycle of mosquito and cockroach is that the cockroach life cycle has been comprised of three developmental phases, the egg, nymph and the adult stage. Most cockroaches are oviparous it means they lay eggs and their young ones grow in the eggs outside the mother's body. These nymphs will be feed and go through a series of the moultings over a period of one year as they develop into adults.
What is oviparous?Oviparous is the animals that lay eggs as their young ones and Most cockroaches are oviparous it means they lay eggs and their young ones grow in the eggs outside the mother's body. These nymphs will be feed and go through a series of the moultings over a period of one year as they develop into adults.
Genetic mutation, crossing over during meiosis, polypoidy is an example of a cause of natural variation to the mechanism of natural selection. Variation shown in many ways such as physical appearance, metabolism, reproduction, fertility behavior, learning and mental ability, such variation is called as natural variation.
Therefore, The description of life cycle of mosquito and cockroach is that the cockroach life cycle has been comprised of three developmental phases, the egg, nymph and the adult stage. Most cockroaches are oviparous it means they lay eggs and their young ones grow in the eggs outside the mother's body. These nymphs will be feed and go through a series of the moultings over a period of one year as they develop into adults.
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Bees mainly eat the nectar of flowers and in the process get pollen all over their leg hairs, which gets carried to the next flower, pollinating them. This is an example of ___________.
A. Conditioning
B. Predator-prey
C. Mutualism
D. Parasitism
Answer:
C
Explanation:
The process of pollination is an example of mutualism. Thus, the correct option is C.
What is Mutualism?Mutualism may be defined as a +,+ interaction in which both species may be benefitted when living together.
During the process of pollination, the host plant will receive the service of insects to provoke the pollination successfully while in return insects get the food (nectar) and space to live on the plant's flower.
Therefore, the process of pollination is an example of mutualism. Thus, the correct option is C.
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Vaccines are
1 point
cures for pathogens
prevent pathogen infection
used to treat a bacterial infection
100% effective
Answer:
To prevent a pathogen infection
which of these sources add water to lakes
Answer:
what are the sources bff
Explanation:
Answer:
Rain runoff, groundwater, melting snow.
Explanation:
Rain flows through various paths and goes into lakes, carrying various types of small leaves or soil particles along with it into the lake.
Groundwater can also form lakes and is the source of freshwater.
The melting snow is also the source of freshwater that flows and reaches the nearby ponds or lakes present in the nearby areas.
How do people get natural dye.?
I am thinking that are from trees but I am not sure pls help me
Answer:
people can get first from anything really
Explanation:
plants like lavander can give a slight purple color and etc
Indigo plants ;And woad is to make violet and blue dyes
What is the potential disadvanatges of external digestion
Answer:
Environmental hazards such as predators reduce the change if surviving into adulthood, Large amounts of gametes go unfertilised and wasted, Not guaranteed that sperm will come in contact with eggs, Greater chance of desiccation of gametes/zygotes.
Explanation:
Which inference can you make about why finches have adapted different beak sizes and shapes? (1 point)
They are different species.
O They live in the same location.
O They eat different foods.
O They have a wide range of variation
Finches have adapted different beak sizes and shapes because they eat different foods. So the correct option is C.
What is natural selection?Natural selection is a mechanism for evolution to happen. It is the process by which living organisms acquire certain characters according to their needs.
It is important to understand natural selection to understand the essential concepts of the processes by which living organisms have been able to develop the complex structures which are helped them to survive.
Natural selection results from various conditions of environment, ecosystem and heredity. An example of natural selection is the development of antimicrobial resistance to pathogens.
Finches are known to have developed different sizes and shapes of beaks according to the kind of food that they eat. If they fed on insects, they had long and pointed beaks. If they fed on seeds and nuts, they had broad and blunt beaks.
Therefore the correct option is B.
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3. What are the two processes underlying this image that turn peat into coal?
A. Lignitigation and coalification
B. Petrification and coalification
C. Peatification and lignitigation
D. Peatification and coalification
Explanation:
D. Peatification and coalification is the answer
hope this helps you
have a nice day:)
Answer:D. Peatification and coalification is the answer
hope this helps you
Explanation:
draw a flowchart showcasing the process of scientific learning .also mention a short description of each of the step in the chart.
Answer:
The scientific method is a system of exploring the world around us, asking and answering questions, and making predictions. Scientists use the scientific method because it is objective and based on evidence. A hypothesis is fundamental to the scientific method. A hypothesis can take the form of an explanation or a prediction. There are several ways to break down the steps of the scientific method, but it always involves forming a hypothesis, testing the hypothesis, and determining whether or not the hypothesis is correct. If the hypothesis is rejected, this does not mean the experiment was a failure. In fact, if you proposed a null hypothesis (the easiest to test), rejecting the hypothesis may be sufficient to state the results. Sometimes, if the hypothesis is rejected, you reformulate the hypothesis or discard it and then go back to the experimentation stage.
The process of scientific learning refers to the various steps via which one can examine and study our environment to understand it. Once understanding or know-how is achieved, then technology is said to have advanced further.
It starts with making observations. Now because of the limitation of our senses, it is important not to jump to conclusions. The next step is to form a hypothesis based on the observation madeWhen you have arrived at a hypothesis, you can now carry out a controlled experiment where you collect further data and reach conclusions based on the experimentIf the hypothesis is in line with your observation, you publish resultsIf the hypothesis is null, you also publish results, then review your hypothesis and repeat the experimentAll the above require consistent documentation at each stage. Please see the attached image for the flowchart.
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match each term to its definition
a steam of plasma
Answer:
The solar wind is a plasma, a stream of charged particles (ions and electrons) that are continuously escaping from the Sun into the interplanetary medium.
Is the Use of energy to move particles against the concentration gradient
Answer:
During active transport, substances move against the concentration gradient, from an area of low concentration to an area of high concentration. This process is “active” because it requires the use of energy (usually in the form of ATP). It is the opposite of passive transport.
What's the common ecosystem of a Paramecium aurelia
Answer:
Paramecium live in aquatic environments, usually in stagnant, warm water. The species Paramecium bursaria forms symbiotic relationships with green algae. The algae live in its cytoplasm. Algal photosynthesis provides a food source for Paramecium.
