The correct answer is B.
The humans forearm is much like a bat wing, because all of our tendons and liniments. Although we do not use the structures in the same ways, they are alike.
whenever humans exhale carbon dioxide, plants take it in and use it to make a mixture of sunlight and water to create nutrients for itself. Once it creates the nutrients it releases oxygen which us humans use to breathe. This operation is called photosynthesis.
The answer is Photosynthesis
It's controversial because the best source of stem cells is a human embryo (an aborted fetus).
