What would be the situation if there is plastid in human cells?

Plastids are mainly used to manufacture and store food. They often have pigments, which affects the colour of the cell. ... Plastids can include chloroplasts, chromoplasts and leucoplasts. Imagining if a human cell has a plastid, we would have turned green and also human cells could have prepared their own food.

Explanation:

Hope this helps

B
Explanation: if you look at A and try to combine like terms, you will add the -x on the right side the the one on the left, cancelling out the x on the left. then you have 0=x+0, and unless x=0, it is not true.
With B, when you add x to the -x, you cancel it out, giving you 0=0, which is true. hope it helps!