The right choice of them is biosphere, community, and organism.
The best answer is B - Proteins.
Proteins make up enzymes, or to put it another way enzymes are made up of protein. It is enzymes that speed up the chemical reactions. Enzymes are organic catalysts, substances that speed up a (biochemical) reaction but do not take part in the reaction and remain unchanged at the end of the reaction.
In man, there are many enzymes. The majority of these are found in the digestive system where they greatly aid the process of food breakdown from complex molecules to simple molecules. Examples include salivary amylase found in saliva, which begins the gradual breaking down of starch into glucose right from the moment food is placed in the mouth and mixed with saliva. Pepsin in the stomach breaks down protein.
Filtered blood leaves the kidney through the renal vein and flows back to the heart. Pee leaves the kidneys and travels through the ureters to the bladder. The bladder expands as it fills.
Ducklings follow their mother due to imprinting.
