Answer:
B--- pay careful attention to what you are observing.
Explanation:
When you go to fast when making observations, you can mess up. When you take your time and pay careful attention when making observations, there is a chance you could mess up, but it is very slim.
<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:
Explanation:
The two main functions of stomata are to allow for the uptake of carbon dioxide and to limit the loss of water due to evaporation. In many plants, stomata remain open during the day and closed at night. Stomata are open during the day because this is when photosynthesis typically occurs.
Explanation:
The evolution of egg was the most important evolutionary incident which allowed the evolution of the terrestrial animals. The amnion is the layer inside the chorion of the egg which keeps the embryo from drying out.
The formation of this layer completely removed the dependency of the organism to lay their eggs in the water to keep them wet.
This layer allowed the reptiles to lay their eggs on the land as the amnion can protect the embryo from drying out. The other layer of eggs protects the egg from the predators and the pathogens.
Thus, the evolution of the amniotic egg is very important from the evolutionary perspective.
