Answer:
The answer is Genetic drift and natural selection.
Explanation:
Genetic drift is a change is genetic composition that enhances organisms adaptation to an environment. The continuous change gives an extra advantage and enhances better chances of survival
Natural selection is the process that results in the adaptation of an organism to its environment by relatively reproducing its genes.
This two factors are the major factors that like causes allele fixation
Answer:
bases.
Explanation:
Nucleotides are the basic building blocks that make up DNA, consisting of a deoxyribose sugar, phosphate group, and nitrogenous base. The main difference between the four nucleotides is the nitrogenous base, Adenine, Thymine, Guanine, or Cytosine. Adenine pairs with Thymine, and Guanine pairs with Cytosine. The order in which these pairs come in code for proteins and hold genetic information.
The correct answer is letter A: the circulatory system removes waste from the tissues by converting carbon dioxide-rich blood into oxygen-rich blood that can be circulated throughout the body to support its several functions. Without the lungs the human body will not be able to process converting blood cells into oxygen-rich cells in the body.