Starfish are able to reproduce both sexually and asexually. in an area of the ocean that is gradually changing due to increasing temperatures, it is more advantageous for starfish to reproduce because they will be able to .

Due to the increasing temperature in ocean it is more advantageous for start fishes to reproduce asexually because they can regenerate via a process called fragmentation.  

In fragmentation, a part of arm or a part of disc is separated from the parent body and grows into a complete new organism; an individual star fish.  

Moreover, regeneration is the ability of an organism to renew, or re-grow any part of the body, makes it resilient to environmental fluctuations.

i think its c. amphipod

a "theory" a suggestion that is not 100 % accurate, or a figure. some people say its a theory because they of all the passed theory's about one subject. it depends sometimes theory might be accurate and sometimes they are.