Answer:
If the type of food available changes, then the frequency of beak also changes.
<span>Cells control cell division in order to maintain normal cell function. If something happens to the control of the cell division, the healthy cells will divide uncontrollably. These new cells are cancer cells. </span>
The mutations in three genes are responsible for development of cancers:
1. Mutation in proto-oncogenes. Proto-oncogenes normally signal cells to grow and differentiate. Proto-oncogenes can become oncogenes due to mutations which result in the uncontrollable division of the cells.
2. Mutation in tumor suppressor genes. In normal cells, tumor suppressor genes suppress genes essential for cell cycle and that way they prevent uncontrollable cell division. However, after a mutation in these genes, suppression is lost and the cell may progress to cancer.
3. Mutation in stability genes. In normal cells, they have no role either in cell death or growth, but they control mutation rate. Mutation in stability genes results in situation where all genes, including proto-oncogenes and tumor suppression genes, are more frequently mutated.
Answer:
The valves' main job is to keep the blood moving in one direction – back up towards the heart. When the valve is open, blood freely flows upward towards the heart and when the valves are closed, blood cannot flow back
Decomposers also break down the bodies of dead organisms resulting in nitrogen being returned to the soil as ammonia. In some conditions denitrifying bacteria in the soil break down nitrates and return nitrogen to the air.
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Answer:
Predation.
Explanation:
Limiting factor refer to resources or environmental condition that limit the growth or distribution of organisms in the ecosystem. This make the organism not to occupy their original niche. Predation is a limiting factor. Predation refer to ability of an organism to prey on another organism or capture it. Predation is a density dependent factor whose effect on population determined the total size of the population. Fox chasing pika is an example of predation.
