A student was studying a soil sample. Most of the inorganic matter the student found included- A. plant roots and animal waste.
B. small sand and clay particles.
C. invertebrate exoskeletons
D. oxygen and plant leaves.

the density(ratio between mass and volume as m/v) decreases from top to bottom in periodic table group as the size increases and nuclear charge decreases. but in periods density increases from left to right as atom size decreases and nuclear charge increases.

particle   p is an electron and particle q is a neutron

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.