Explain why the majority of genes in an organism occur in pairs.

Diploidy

Explanation:

The majority of genes in an organism occurs in pairs mainly because the organism is diploid: it has two copies of most genes—one copy of the gene from each of its two parents.

the answer to your question is:

c. complementary base-pairing

ans.

gregor john mendel is known for study of inheritance in pea plants. he used garden pea plant for his study, having alternative traits for various characters. he performed cross-breeding in pea plants to check how characters are transmitted between parents to offspring, such as cross between pure tall and pure dwarf plant. mendel studied the inheritance patterns in pea plants for various generations.

thus, the correct answer includes options and f).