Question

One adaptation that is unique to marine mammals is they

can slow their heart beat down.

are warm-blooded.

breathe air through their lungs.

nurse their young.

Answer 1

what do you think

Answer 2

you can eliminate stuff that's not unique

eg: choice B is "are warm-blooded." but all mammals are warm blooded, so that's out

Answer 3

btw I'm not that great at bio, but luckily I do know the answer to this one at least

Answer 4

are marine mammals the only mammals that breathe air through their lungs?

Answer 5

so that's eliminated

Answer 6

that's the only thing left (since all mammals nurse their young)

Answer 7

so while I wouldn't have gotten the answer directly (since I didn't know that, that's pretty cool actually), it's still possible to get it indirectly like this

Answer 8

yw