Answer:
Visible light contains all the colors from violet to red. An object gets its color when electrons absorb energy from the light and become “excited” (raised to a state of increased energy). The excited electrons absorb certain wavelengths of light.
The Sun emits light of every possible frequency at once, including at frequencies too high or too low for us to see. But the Sun's highest intensity radiation aligns approximately with our visible range – red through blue. That's no coincidence – like all animals on Earth, we have evolved to make best use of the light available.
Explanation:
Answer : A - carboxyl group.
The carbon in the carboxyl group is bonded to a hydroxyl group and also it is double bonded to an oxygen group.
The carboxyl group when it is dissolved in a solution donates it's hydrogen ion(H+ ion). When it is dissolved in water, the carboxyl group loses its H+ ion to form negatively charged ion.
RCOOH + H2O⇄RCOO- + H3O+
Thus the carboxyl group act as an acid when dissolved in water.