Answer
b
Work Step by Step
Option a. is incorrect. Some organisms are hermaphrodites, meaning they have both male and female sexual organs and can fertilize one another. Others can self-fertilize.
Option c. is incorrect. Optimal environmental conditions usually favor asexual reproduction.
Option d. is incorrect. Sexual reproduction does not have to occur in aquatic habitats. Land animals and birds can also reproduce sexually.
Option e. is, therefore, incorrect.
Option b. is correct. Gametes, or sex cells, unite to form a single cell that grows into an individual that is different from its parents.
