Which scientist developed ideas about natural selection at the same time as darwin?

Where do the respiratory and circulatory systems meet? a. in the heart b. in the muscles c. in the lungs d. in the brain

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.

Vessels draining the myocardium of the heart, open primarily ,into which chamber?