D, because skin tans to help us stand being in the sun without getting burned.
An example of physiological adaption is being able to digest milk. Before, humans were not able to digest milk before we developed enzymes that now make us have the ability to do so, thus allowing us another food source.
The respiratory system always needs iron. The red blood cells are in charge of the transport of O2. They need iron to do this.
Hope this helps! :)
the temperature of mercury is not regulated and the atmosphere easily floats away while being replaced with solar wind .
Mercury has a thin atmosphere.
Answer:
An atom is the smallest component of an element that still has the properties of that element.
Atoms are made of three particles. protons, neutrons, and electrons.
Explanation:
