(A) The primary property of the pigment (chlorophyll) responsible for initiating photosynthesis is its ability to absorb light energy and become excited,leading to the emission of high-energy electrons $(e^-)$.
$1$. When chlorophyll molecules absorb light,they reach an excited state and lose electrons. These electrons are then transferred to an electron transport system.
$2$. The electron deficiency in chlorophyll is compensated by electrons derived from the photolysis (splitting) of water molecules.
The rate of photosynthesis is higher in the red and blue regions of the light spectrum because:
$1$. Chlorophyll pigments have peak absorption spectra in the blue ($430-450$ $nm$) and red ($640-680$ $nm$) wavelengths.
$2$. These wavelengths fall within the Photosynthetically Active Radiation $(PAR)$ range ($400-700$ $nm$),providing optimal energy to excite the electrons required for the light-dependent reactions.