Whales are tetrapods- but living whales do not have four limbs. Describe a more accurate way to describe tetrapods BESIDES having four limbs?

Which of the following is the best definition for the process of photosynthesis? a.) plants digest sugars to make energy. b.) plants use oxygen and glucose to make carbon dioxide. c.) plants use sunlight and carbon dioxide to make sugars. d.) plants use sunlight to make chlorophyll and chloroplasts.

Idon’t know the answer and i’ve been stuck on it for a while now skskskskks

Which of the follow describes a disadvantage secondary sources have compared to primary sources?