What type of molecule is represented by the model below? a : fat b : carbohydrate c : steroid d : protein

Explain how scientists use geologic time to determine the age of landforms.

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?

This is a biological reaction due to a stimulus. i need this quickly !