Hello,
I believe you're asking which option is true. If so, A) do not require a medium. Unlike mechanical waves, electromagnetic (or light) waves do not require a medium. It has been proven that light travels in a straight line. Light waves are, in fact, electromagnetic radiation, and they can travel in a vacuum.
Faith xoxo
Answer:
https://www.biology-pages.info/T/Tropisms.html
Explanation:
This link holds all the information you need :D
<span>Active transport works to conserve homeostasis. When cells are doing something they typically receive a signal causing channels to open, which in turn lets in a flood of molecules down their chemical gradients. Hope this answers the question.</span>
