Fertilization results in a. a nucleus. b. an ovum. c. gametes. d. a zygote.

D. a zygote.

Explanation:

Fertilization is a precursor of reproduction process which involves the fusion of the haploid gametes that are egg and sperm. This process will yield a diploid zygote. The zygote is a precursor of new life. The fertilization process may either occur inside the female mate body, called as internal fertilization or outside the female body called as external fertilization.

The zygote undergoes differentiation until specialized parts develop in a living fetus.

i think the answer is

mass

d. planting trees

the trees take in carbon to make oxygen.