Identify the positively-charged sub-atomic particle in the nucleus. a) electron b) neuron c) neutron d) proton

D) Proton

Explanation:

In an atom there exist three types of sub atomic particles

1) Electrons

2) Neutrons

3) Protons

so we know that electrons are negatively charged particles which stays in a finite orbit as per their energy level

Protons are positively charged particles which remains inside the nucleus and they are tightly bound inside it

Neutrons are neutral sub atomic particles which do not have any charge in it.

So we have correct answer as

D) Proton

the part of the wave he is travelling on is the crest

one "light year" is the distance that light travels, through vacuum, in one julian year.   that's 365.25 days, of 24 hours each.