The nucleus of the atom composed of what subatomic particle(s)? A Neutrons and Electrons B Protons and Neutrons C Protons and Electrons D Protons and Electrons

B Protons and Neutrons

Explanation:

The nucleus of the atom discovered in 1911 by Ernest Rutherford from the  Geiger–Marsden gold foil experiment consists of protons and neutrons at the center of the  atom which are  are bound together  by a nuclear force.

The nucleus has two basic properties which are the mass and charge of which the proton is positively charged having +1 and the neutron having a neutral charge at zero . Both are denoted with mathematical numbers: Z- proton and  N-neutron and their addition gives the mass number,A.

Both protons and neutrons have a mass of 1 amu.

if you already have the answer to (a), then just work out how many periods there are in 1 minute, and that's the answer to (c).

a and c

c is 100% but i am confused in a