Which statement best describes a human chromosome? a. It is made of amino acid subunits that forrigenes.
b. It contains genes that may code for the production of enzymes.
C. It is normally passed to the next generation through a placenta.
d. It varies in function from one generation to the next.

answer: land bridge theory. land bridge theory held that shifting portions of dry land explained the finding of identical species on different continents. plate tectonic theory eventually eliminated the land bridge theory.

the answer is "a.) well–developed vascular system."

explanation:

your body is trying to warm itself up. or more precisely, sensors in your skin send messages to your brain to generate heat to your body.