The difference between the structure of Magnesium -26 and magnesium -24 is A. different number of protons
B. different number of electrons
C. different number of neutrons
D. no difference

I’m stuck on this question cuz i’m stupid sksksksk

This is the main structural axis of the plant that supports leaves, flowers and fruits; transports fluids; stores nutrients and produces new tissue.

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?