HELP I DONT GET THIS

What is a general feature of a species that varies from one individual to the next (skin tone,eye color or hair color)? a.organism b.trait c.character

Just a quick question. will give pointswhat is the root word of "blood."it is written in my homework as hemat(o) : blood.so, should i write that the root word as hemat or hemato or hemat(o). i'm really confused.

There are two tomato plantlets one of them is kept in an oxygen chamber with a light source and another is kept in sunlight. both of them are watered regularly what will be the observation after two weeks