Given the task definition and input, reply with output. Given a scientific passage and an answer, generate a question for the given answer.

Passage: Monotremes reproduce by laying eggs. They have a cloaca instead of a uterus and vagina. The eggs pass through the opening of the cloaca. This form of reproduction is the least risky for the mother. However, eggs are harder to protect than is an embryo or a fetus in a pouch or uterus. Therefore, monotreme offspring may have a lower chance of surviving than the offspring of therian mammals. Answer: by laying eggs
How do basal mammals like monotreme reproduce?