Only the last one provides an actual evidence of having a common ancestor. The rest can be a result of living in a similar environments that makes life easier. For example, many species live next to water, as water provides more fertile ground for plants, and they might have similar behaviors (searching for water) but they might not be closely related.
so the correct answer is D.
NO, the ocean is salty because it is the place where many of the salt from lakes and rivers leave off in. If this doesn't happen, then there will not be any fresh water, there will only be salty rivers, very salty rivers, not so salty rivers, or so salty to the point you can't even drink it salty water (lol)
hope this helps
I believe the answer you're looking for is Evolution.
Answer:
fertilization
Explanation:
this often results in genetic variation as well :)
Answer:
chemical, mechanical, electrical
Explanation: