Question

Organelles, cells, tissues, organs, and organ systems work together to build, break down, take in, and transport many types of __________ that are essential for life.

Answer 1

I think the answer should be proteins.

There are 3 macromolecules that essential for life: carbohydrates, proteins, and lipid. Carbohydrate is used as the main energy source. It mostly comes from food and doesn't need to be built. Protein is used to built organelles. Some of them will work as an enzyme that will break down molecules. Unlike carbohydrate and lipid, there are many types of protein that can be formed. 

Answer 2

It would be molecule