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3 years ago

How does using a ramp make work easier when loading a piano onto a truck three feet above the ground

2 answers:

4 0

The ramp on an automobile transport truck is used to lift cars high into the air. An inclined plane makes it easier to raise something heavy, like a rock. Instead of lifting the rock straight up, you can raise it from its original location with less force by pushing it up a ramp.

matrenka [14]3 years ago

3 0

The correct answer is

D. It allows a smaller force to be applied over a longer distance.

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What are the two phases of speciation?

Anna007 [38]

Phase 1: Starts with the separation between populations. Separated populations become adapted to local conditions and become genetically differentiated over time.

Phase 2: Genetic isolation is completed, reproductive isolation develops mostly in the forms of prezygotic RIMs.

6 0

3 years ago

Read 2 more answers

Write exactly 60 biological words about a cactus as plant

lukranit [14]

Explanation:

hope it's help you dear

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6 0

3 years ago

PLEASEEE HELLPPP PLEASEE SOMEONE ANSWERR THISSS PLEASEEEEEEEEEE

vichka [17]

1) Natural Selection- General speaking, something must cause differential reproduction and then better suited individuals will survive over time.

- Detailed Explanation -

Natural selection is the process in which individuals whom are better suited to their environment will have an increase in fitness. It occurs over multiple generations and can take a very long period of time to occur.

For natural selection to occur, the following must be true:

1. There must be variation in traits (every individual can't be identical)

2. There must be differential reproduction (some individuals are more likely to reproduce than others)

3. Traits are passed on from generation to generation

Thus, the first step in natural selection is that something must cause differential reproduction. This could be the introduction of a predator, a disease, a random mutation that is detrimental, a change in resource availability such as a drought, and so forth.

This image shows how a genetic mutation is unfavorable and is selected against, but the same process holds for a gene that is unfavorable during any scenario.

This event causes some individuals to survive and reproduce and some to be less successful. For example, a predator is introduced and it hunts and kills mostly individuals with shorter legs that run slowly. Or the environment undergoes a long drought and individuals in the species who have a gene that helps them perspire (sweat) less are more successful.

Over multiple generations, the genetic composition of the species changes. Maybe within six generations the predator has completely wiped out individuals with shorter legs. Maybe within two generations the drought completely eliminates individuals with a gene that results in excess perspiration. The amount of time will vary.

2) Mutation - A change in the genetic structure of an organism.

Explanation:

Usually, a mutation has to be expressed as some macro-functional characteristic although some may be hidden in internal systems.

3) Genetic Drift- Genetic drift is the change in the frequency of an existing allele in a population due to random sampling of organisms.

Explanation:

The effect of genetic drift is larger when there are few copies of an allele, whereas when there are many copies the effect is smaller.

Genetic drift describes random fluctuations in the number of gene variants in a population. Once it begins, genetic drift will continue until the involved allele is either lost by a population or until it is the only allele present in a population at a particular locus. Both possibilities reduce the genetic diversity of a population.

Genetic drift can cause a new population to be genetically distinct from its original population, which has led to the hypothesis that it plays a role in the evolution of new species.

4) Gene Flow- Gene flow is a concept in population genetics to refer to the movement of genes or alleles between interbreeding populations of a particular species.

Explanation:

Gene flow is an important mechanism for transferring genetic diversity among populations. Migrants into and out of a population may result in a change in allele frequencies, thus changing the distribution of genetic diversity within the populations. High rates of gene flow can reduce the genetic differentiation between the two groups, increasing homogeneity.

It is thought that gene flow constrains speciation by combining the gene pools of the groups and thus, prevents the development of differences in genetic variations that would have led to full speciation. It is expected to be lower in species that have low dispersal or mobility, occur in fragmented habitats, there is a long distance between populations, and smaller population sizes.

It includes different kinds of events, such as pollen being blown to a new destination or people moving to new cities or countries. However, there are certain factors that serve as barriers to gene flow. Some of the factors affecting the rate of gene flow include physical barriers, geological events and geographical barriers.

5)Non Random mating- The nonrandom mating is a selective pattern.

Explanation:

The nonrandom pattern of mating is an assortative pattern of sexual reproduction. During the reproduction, similar phenotypes are selected for mating. It is a random process. It is also known as positive assortative mating.

7 0

3 years ago

In the human population there are 3 alleles that control blood type. alleles a and b are codominant, while allele i is recessive

anyanavicka [17]

The theoretical percentage of their offspring that will have blood type O is 25 percent

5 0

3 years ago

11. Where do the direct sun's rays hit during the spring and fall equinox?

kherson [118]

Answer:

After the vernal equinox, the most direct rays of the sun striking the earth continue to migrate north. On June 21/22, the most direct rays of the sun fall on locations situated at 23.5 degrees north latitude.

5 0

3 years ago

Read 2 more answers