Question

The carbon that plants need for photosynthesis comes from
A.
carbon molecules dissolved in water.
B.
carbon dioxide gas in the atmosphere.
C.
carbon atoms from the breakdown of food.
D.
carbon molecules that the plant produces.

Answer 1

B. Carbon dioxide gas in the atmosphere.

Plants take in CO2 through stomata in their leaves and use the carbon from CO2 to build sugars (photosynthesis).