1. Which statements about nuclear fission and nuclear fusion are true? Select the two correct answers. They both occur in the nucleus of an atom.
They both involve two atoms fusing into one atom.
They both involve one atom splitting into two atoms.
They both release large amounts of energy.

Most elements have more than one naturally occurring isotope. as you learned previously, the atoms of those isotopes have the same atomic number (number of protons), making them belong to the same element, but they have different mass numbers (total number of protons and neutrons) giving them different atomic masses. so which mass is put on the periodic table for each element? is it the most common isotope’s mass? the heaviest mass? this activity will answer that question.

Ibelieve this is not the full question but a lead is visual similarities   

The answer is the bike has rolling friction, the sled and the motorcycle have sliding friction, and the elephant has static friction 

Ibelieve it would be b). circulatory.