If titanium has 22 protons in its nucleus how many neutrons are present in the nucleus of its most common isotope

When lactate builds up in a runners muscles it causes a burning sensation what causes this to occur

Which of the following explains why a tree is often used as a model to represent the principle of common descent

Ihave no idea how to solve these. plus there's another question that is 2) a 10 kilogram meteorite is collected in space and brought back to earth. it is composed of 1.25 kg of uranium-238 and 8.75 kg of lead-206. how many u-238 half lives have passed? what is the approximate age of the meteorite?