The answer is; D
Radioactive waste poses a serious challenge to the environment. Any leakage of the waste is risky because the radioactivity can flow up the food chain and it also takes time for it to decay and become less harmful. Therefore, its effect can be felt over many generations. Therefore, safe storage of radioactive waste is a challenge (and can be very expensive) and a deterrent for pursuing the potent energy source.
Answer:
<em>When a queen gets old or weak and slows her production of queen substance, she is generally replaced by a new queen. New queens are also produced in colonies about to swarm. Virgin queen bees take what is known as a "nuptial flight" sometime within the first week or two after emerging from the pupal chamber.</em>
Homeostasis is maintained by the respiratory system in two ways: gas exchange and regulation of blood pH. Gas exchange is performed by the lungs by eliminating carbon dioxide, a waste product given off by cellular respiration.