It's generally accepted that the first life on Earth was unicellular and, while autotrophic, did not have chlorophyll. Later multi-cellular, chlorophyll-bearing organisms evolved. Speculate on how amoeba-like organisms that lacked chlorophyll might have obtained the ability to use chlorophyll to capture the energy of the sun.

The theory of endosymbiosis has an intriguing logical history. German naturalist Robert Lauterborn found plant cells inside the single adaptable cell. It had two huge, frankfurter formed plastids named chromatophores, which helps in photosynthesis. He proposed this speaks to the beneficial interaction of two cells, this revelation helped in the advancement of endosymbiosis.  

The Earth is green on the grounds that photosynthetic plants and green growth contain chlorophyll, a green color that reflects green frequencies of light. About 1.5 billion years back, an algal predecessor (single adaptable cell) immersed a photosynthetic bacterium, lessening it to a chloroplast, a plastid with chlorophyll. What's more, utilize its hereditary data to make own nourishment and it additionally offered ascend to the advantageous interaction (heterotrophic creatures) that relied upon the plants for the nourishment. One-celled critter inundated the bacterium, kept that cell alive and outfit its qualities for photosynthesis.

b.have there own function.

this is true, assuming that the allele is completely recessive and incomplete dominance is not a factor.