A) a common ancestor
Homologous structures are structures that are similar in related organisms. There is a basic pattern of bones which can be inherited from a common ancestor
The order in which the amino-acids are placed within the polypeptide determines the tertiary structure and therefore the function of the given protein. Amino acids have different functional groups like methyl(CH3), phenyl(C6H5). Those functional groups can interact with molecules like glucose determining reactions, the proteins that catalyze reactions are called enzymes. Other functional groups of amino acids can be the sulfate groups. For example, insulin has 2 polypeptide chains(Chain A has 21 amino acids, and chain B, 30). Between the two polypeptide chains, 2 disulfide bonds form altering its shape.
The answer is fusion of gametes via fertilization.
Answer:
Because it is formed by rocky materials
Explanation:
These planets are small and of high density, mainly by transparent and rocky materials with a well differentiated internal structure and a similar size.
They tend to be more dense since it is formed of rocky and non-gaseous materials like the higher planets.