Dichotomous key ask
a. open-ended questions about animal behavior
b. open-ended questions about easily observable characteristics
c. yes-and-no questions about animal behavior
d. yes-and-no questions about easily observable characteristics

Dichotomous keys ask D. yes-and-no questions about easily observable characteristics. So, these questions are there to identify a specific organism, by asking specific questions about some characteristics of that animal in order to determine which one it is. For example, Does this animal have feathers?. etc.

The answer to this question is D.

The proton has a positive charge while the neutron has no charge they both make up the nucleus of the atom while the elections have a negative charge and surround the nucleus of the atom. the protons and electrons are used to calculate the atom's mass whereas the neutrons don't affect the mass

Idk i think the answer choice is number 1