The best answer would be "research reasons why species change over long periods of time"
if not i apologize but this is my best guess<span />
Answer:
Attached R side groups
Explanation:
The proteins are one of the important biomolecules which are directly coded by the genetic material of an organism.
The proteins are composed of the amino acids which possess, an amine group, a carboxylic group and an attached side group called the R group.
It is the R group of an amino acid which determines whether the amino acid will a polar or a non-polar amino acid molecule thus it determines the properties of the amino acid in terms of chemical properties. The R side group are involved in the formation of bonds with the substrate of the environment and the tertiary structure of the proteins.
Thus, the presence of different R group is the key difference in 20 amino acids.
The second phase of general adaptation syndrome (gas) is characterized
by alarm phase, the stage of resistance and the exhaustion stage. The gas stage gives a description of the both
the short and long term emotional and physical effects of stress. Gas elaborates the relationship between
health and stress.
The best answer is A.
Mitochondria are small organelles found floating free in the cytoplasm of both animal and plant cells. They consist of two membranes, an outer and inner membrane which has numerous folds creating layered structures called cristae.Inside the mitochondria, there is found fluid called the matrix
Mitochondria are the powerhouse of cells. Many of the reactions in cellular respiration that take place in the cell occur in mitochondria and thus these organelles are key in the production of energy .