Why carbon is considered the building block for life?

Which direction does the energy flow in this energy pyramid ?

In the respiration-photosynthesis cycle shown above, what are the products of cellular respiration that belong in box 2?

Which of these statements is true about autotrophs, but not heterotrophs? a. they use sugar and oxygen to make carbon dioxide and water.b. they use chlorophyll and oxygen to make carbon dioxide and water.c. they use sunlight, water, and carbon dioxide to make sugars.d. they use sunlight, water, and oxygen to make chlorophyll.