The answer is almost definitely A seeing as the others are either based on the need to breathe (d) or body parts (b and c). Hope this helped. <span />
This answer is true as can be!
If a star is a brilliant blue color, it's really hot and emits a lot of energy. If it's red, it has a cool surface temperature instead. Therefore, the dominant wavelength of a star's light can tell us its surface temperature.
B .The membrane is what separates, and is the system boundary.<span />
