When scheduling animal studies with rats, the researcher must be aware of the implications of scheduling because: a.            Rats show a preference for activity when they are not watched....

When scheduling animal studies with rats, the researcher must be aware of the implications of scheduling because:

a.            Rats show a preference for activity when they are not watched.

b.            Rats are more active in the dark phase or night.

c.             Rats are too fast to be observed accurately.

d.            Rats may refuse to cooperate.

e.            Rats may fall sick often and have to be replaced.