The studies are designed this way b/c it removes the power of suggestion and the double-blind study keeps both researchers and participants in the dark. So this compared to who is receiving the treatment which is relevant b/c it stops the researchers from accidentally overbalancing the study participants, or unintentionally favoring their assessment of the conclusions.
If you do not have variations to be selected by natural or sexual selection on their superior abilities to survive and reproduce successfully then nothing can be naturally selected against the immediate environment.
<span>B.) It is moving away from Earth.</span> When an objects moves far from the viewer, it's light is affected by a change called doppler effect or doppler shift.
I also believe it is C.
All of these organs, skin, lymph nodes, white blood cells, and spleen, act to enhance human immunity.
