Explanation:
Carbohydrates are the main energy source of the human diet.
Fats are also a source of energy but fats are the slowest source of energy.
Explanation:
Karyotyping is <u>a test to examine chromosomes in a sample of cells</u>. This test can help identify genetic problems as the cause of a disorder or disease.

The answer could possibly be natural selection or survival of the fittest