Human muscle cells compared to blood cells all contain the same number of chromosomes with the same complement of genes. Yet, the hemoglobin protein which helps to temporarily bond to oxygen is found in blood cells and not muscle cells. Which of the following best explains this difference? A. Some cells have the ability to remove unnecessary DNA sequences.
B. Different cell types use different methods of cell division.
C. There was a mutation of the genes within each cell type.
D. The expression of genes is regulated in different cell types.

Which is an important function of normal flora? a. aid with bone marrow production. b. crowd out pathogenic bacteria. c. destroy digestive track pathogens. d. manufacture iron in the bloodstream.

Drag each tile to the correct box. the body monitors the levels of oxygen in the blood to regulate breathing. isabel is running in a marathon and is near the finish line. she feels out of breath. how will her nervous system work to generate a reaction? arrange the tiles in chronological order. isabel's breathing rate increases. sensory receptors in the arteries detect low oxygen levels. the brain sends signals through motor neurons. sensory neurons generate an impulse. the central nervous system relays an impulse to certain brain regions.

Differentiate renewable and nonrenewable resources