A mechanical wave is created when a source of energy causes .
A. a vibration to travel through a medium
B. a displacement that must be filled
C. the structure of a medium to be altered

Harry lives in a city, and he has a lung condition known as asthma. on certain days, harry has to stay inside because pollutants in the air make it difficult for him to breathe. which of these pollution sources are nonpoint sources that might bother harry if he goes outside? choose the two that apply.

In medium-sized stars such as the sun, nuclear fusion almost always means the fusing of nuclei to form , but larger stars can produce elements as heavy as

Which of the following is a reason to make an armature the parent of a creature