What is a real life example of a nucleus? give me something that is non-living.

Which of the following is a macronutrient? carbohydrates lipids amino acids all of the above

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?

What chemical speeds up the process of decomposition in dead organisms are exposed to it? nitrogen oxygen hydrogen chlorine