The pulmonary circuit and the circuit make up the blood vessels of the body.
a. capillary
b. blood
c. flexible
d. systemic user: pulmonary circulation transports oxygen-poor blood from the right ventricle to the where blood picks up a new blood supply.
a. heart
b. lungs
c. brain
d. extremities

Ihave no idea how to solve these. plus there's another question that is 2) a 10 kilogram meteorite is collected in space and brought back to earth. it is composed of 1.25 kg of uranium-238 and 8.75 kg of lead-206. how many u-238 half lives have passed? what is the approximate age of the meteorite?