Given a scientific question, generate a correct answer to it.

[Q]: Ocean ridges formed by marine invertebrates living in warm shallow waters within the photic zone of the ocean are called what?
[A]: coral reefs

[Q]: What has a bigger impact on water quality, natural events or human activity?
[A]: human activity

[Q]: The most common mode of asexual reproduction is through the formation of asexual these?
[A]:
spores