Answer:
C, there is genetic variation within the population
Explanation:
The answer should be proteins. Because the protein is consists of different kinds of amino acids(usually 20 in total). And our cell can not produce essential amino acids itself.
They might die because they need salt water to survive.
oye no me lo de baja enviar y me tocó tomarle pantallazo de lo que estaba escribiendo y espero te ayude