The correct answer is "Few in the band have learned all of their music yet". When a verb agrees with its pronoun subject, it needs to sound natural. "Neither" and "either" always agree with a verb in singular form, and "anybody" agrees with a verb in the singular form as well.
Using 1000 plants, each for an individual barrel. The plant that was poisoned will die within thirty days, that way the people will not die. Personally I don't see what's so bad about using 1000 humans as text subjected though ;)
The commutative property states
a x b = b x a
So 4 x 5 = 5 x 4 = 20
So both equal to 20