What does it mean when a compound’s chemical formula does not include any numbers?

there is only one atom of each element.
there are only single bonds in the molecule.
all the atoms have double bonds.
the molecule does not have any bonds.

Match each organ or function with its body system. produces urine large intestine ureters mouth filters blood absorbs nutrients from food

Sammi is studying the interaction of the digestive and circulatory systems in the human body. she has listed various processes that occur in each of the systems. put the processes in order to describe the interaction between these two systems. tiles nutrients diffuse through the villi of the small intestine.digestive processes break nutrients down in the mouth, stomach, and small intestine.blood is pumped through the circulatory system to deliver nutrients to other organs.nutrients are ingested at the mouth.nutrients enter the capillaries of the circulatory system. sequence

What is the most appropriate method of gaining weight (muscle mass)