Answer:
Stars are classified by their spectra (the elements that they absorb) and their temperature. There are seven main types of stars. In order of decreasing temperature, O, B, A, F, G, K, and M.
Explanation:
O and B stars are uncommon but very bright. M stars are more common but dim.
B:Selection is your answer
I believe the correct answer to your question is option A. Black moths were selected for when the trees turned black.
Hope I could help! :)
Answer:
(d)All cells don't have to have cell membranes if they have cell walls to protect them. Cell walls are quite strong and stiff.
The answer is through facilitated diffusion. It is then called as the transport of substances in a biological membrane from a higher concentration to a lower concentration area though carrier proteins. Hope this is the right answer and would be of help.