The krebs cycle is considered a cycle because?
a. the pyruvic acid never leaves the cytoplasm
b. the citric acid formed remains in the mitochondria for the next acetyl coa
c. carbon dioxide is produced as a waste
d. the reaction can go both ways

The right answer is B.

The Krebs cycle is based on modifying a citrate molecule through enzymes and cofactors. It comprises eight enzymatic reactions that can be decomposed into simple reactions. The cycle thus generates eight different molecules including a new citrate at the end of the cycle. In order, it produces initially citrate, isocitrate, alphaketoglutarate, succinyl CoA, succinate, fumarate, malate, oxaloacetate and regenerated citrate upon arrival. The citrate is reformed, so it is a cycle. A complete turn of the Krebs cycle provides the cell 11 ATP + 1 GTP, a total of 12 ATP.

igneous rocks which formed by the crystallization of magma at the surface of the earth called extrusive rocks. they are characterized by fine-grained textures because the rapid cooling at or near the surface did not provide enough time for large crystals to grow.