Some protozoans have special organelles called contractile vacuoles that continually eliminate excess water from the cell. The presence of these organelles tells you that the environment Some protozoans have special organelles called contractile vacuoles that continually eliminate excess water from the cell. The presence of these organelles tells you that the environment contains a higher concentration of solutes than the protozoan. is isotonic to the protozoan. is hypertonic to the protozoan. is hypotonic to the protozoan.

carbohydrates: (starches and sugars) composed of carbon, hydrogen, and oxygen.

lipids: (fats, oils, and waxes) are made of carbon and hydrogen atoms.

nucleic acids: contain hydrogen, oxygen, nitrogen, carbon, and phosphorus. they are polymers of nucleotides. a nucleotide has three parts, a 5-carbon sugar, a phosphate     (-po⬇️4) group, and a nitrogenous base.

proteins: made up of nitrogen, carbon, hydrogen, and oxygen. they are polymers of amino acids.

they fuse to form they have half as many chromosomes as a somatic cell of the same individual. b

the tricuspid valve is present between right atrium and right ventricle