2A + 3B -->C + D When 5 units of A and 6 units of B are allowed to react, the limiting reactant would be:

The limiting reactant is B.

Explanation:

The equation for the reaction is given below:

2A + 3B —> C + D

The limiting reactant can be obtained as follow:

From the equation above,

2 units of A reacted with 3 units of B.

Therefore, 5 units of A will react with = (5 x 3) /2 = 7.5 units of B.

From the calculation made above, we can see that it will take a higher unit of B i.e 7.5 units than what was given i.e 6 units to react completely with 5 units of A.

Therefore, B is the limiting reactant and A is the excess reactant.

the answer is b because, investigating whether another species of moth also drinks tears might be interesting, but it would not directly explain why this species of moth does.

to explain why this species of moth drinks tears, the scientist could ask: "what nutrients that moths need are in elephant tears? "

the scientist could experiment with moth repellent or oter ways to keep the moths away, but that would not answer his original question.