What choice best describes a wind that is caused by a convection current? A: Warm air is more dense than cool air, so the warm air rises and cool air sinks and takes it's place creating wind.

B: Warm air is less dense than cool air, so the warm air rises and cool air sinks and takes it's place creating wind.

C: Cool air is more dense than warm air, so the cool air rises and warm air sinks and takes it's place creating wind.

D: Cool air is less dense than warm air, so the cool air rises and warm air sinks and takes it's place creating wind.

Embryonic stem cells are cells derived from an embryo. these cells can be used to create new tissues for patients suffering from certain illnesses and disorders. which statement best summarizes why the use of embryonic stem cells could be seen as unethical? a. some people consider embryos to possess rights equal to those of fully developed human beings. b. extracting stem cells from embryos is a very energy-intensive process, which consumes resources that could be used elsewhere. c. embryos are difficult to obtain, so the monetary cost of using them for research outweighs their benefit. d. the process of extracting stem cells from embryos generates biohazardous waste that cannot be safely disposed of.