Which grade of eggs is the thickest white and has the roundest and most upstanding yolk?
1. a
2. b
3. aa
4. bb

AA

Explanation:

Eggs are classified based on their quality. As per quality it is categorized into grade AA, A, BB, B. The highest grade of eggs is AA.

The eggs that are marked as AA has thickest white and firm. They have high yolk in them and are usually free from defects.

They do not have any stains on them. They are best both from exterior and interior. This classification of Eggs is given by USA guidelines.

Hence, the correct answer is Option C

genetic variation can be caused by mutation (which can create entirely new alleles in a population), random mating, random fertilization, and recombination between homologous chromosomes during meiosis (which reshuffles alleles within an organism's offspring).