Each member of a class sampled a piece of ptc testing paper. thirty people sampled the chemical. twenty persons were tasters. how many had heterozygous genes? 10 20 0-20 indeterminate

What happens when the cell copies its chromosomes

Which of the following would be a body response when stepping outside without a coat on a snowy day? a. senaceous glands. secrete more senum b. more liquid is transported by the body to the skin fir insulation c. blood vessels in the skin narrow and contract d. blood vessels in the skin expand

Veins have a much lower blood pressure than arteries. which of these prevents backflow of blood in veins? a. pressure applied by the heart b. one–way valves in veins c. thin muscular walls of veins