Electron a emits mainly violet light when excited. electron b emits primarily yellow light when excited.

what can be said about the transition between energy electrons a and b?

the distance between the energy levels for atom a is greater than for atom b.
the distance between the energy levels for atom a is less than for atom b.
the number of energy levels jumped by electrons is more for atom b than for atom
the number of energy levels jumped by electrons is more for atom a than for atom

Explanation:

When electrons are excited they gain energy, which means that they jump from a lower energy level to a (or several) higher enery level (s). Later, the excited electrons will come back the the ground state, i.e. they will jump back to the lower enery level, by emitting radiation in the form of light.

The higher the jump, this is the greater the difference between the energy levels, the higher the energy of the light emitted.

The energy of a photon of light emitted is proportional to the frequency of the light. That is shown by the Planck-Einstein equation: E = h × υ (where E stands for energy, h for the Planck's constant, and υ for the frequency of the light).

Thus, the higher the energy the higher the frequency.

The frequency order for the visible light is: Violet > Blue > Cyan > Green > Yellow > Orange > Red.

Thus, the violet light emmited by electron A has a much higher frequency than the yellow light emitted by electron B.

Since, the distance between the same kind of energy levels for the atoms is nearly the same, that means that the electron of atom A jumped more energy levels than the electron of atom B.

The figure attached (which any one can find in internet) permits to see that an electron that jumps from the energy level n = 6 to the energy level n = 2, emitts a violet light (yellow color is not shown, but it is next to green, so the image can help you to see that this corresponds to a jump of less energy levels).

the answer is b & c i believe : )

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.