Answer:
Animals take in oxygen and give off carbon dioxide.
Explanation:
This is because plants take in our carbon dioxide and give off the oxygen that we as people and animals need to breathe.
Yes it is valid all the times under the consideration of acceleration due to gravity .it is not valid on space where there is no influence of gravity
Nothing happens to the mirror.
However, if the ray is within some suitable range of
wavelengths, the ray is reflected from the mirror's surface.
The energy carried by the incident light is

where h is the Planck constant and f is the frequency of the light. The threshold frequency is the frequency that corresponds to the minimum energy needed to eject the electrons from the metal, so if we substitute the threshold frequency in the formula, we get the minimum energy the light must have to eject the electrons: