Internal and external fertilization both . Select one: a. produce single-celled zygotes b. occur only among invertebrates c. occur only among terrestrial animals d. depend on the use of copulatory organs e. occur only among birds

Option-A

Explanation:

Fertilization refers to the fusion of the male and female gamete to form the zygote.

When the fertilization occurs inside the organism through insemination then it is known as the internal fertilization and when it occurs outside the organism like observed in the amphibians when male and female gametes fuse in the water is known as external fertilization.

Both are different type of fertilization but share a similarity that is the formation of a single cell called the zygote which grows into the embryo by the mitotic division. The embryo later develops into the organism.

Thus, Option-A is correct.

the missing space is phylum

for example, no new evidence will demonstrate that the earth does not orbit around the sun (heliocentric theory), or that living things are not made of cells (cell theory), that matter is not composed of atoms, or that the surface of the earth is not divided into solid plates that have moved over geological timescales .