We inhale oxygen when we breath and exhale CO2. What is the oxygen used for and where does the CO2 come from? a) The oxygen is used during the electron transport phase of cellular respiration. The CO2 we exhale is formed during the citric acid cycle when the bonds in carbon compounds are broken.
b) The oxygen is used as an energy source for our cells. The CO2 is produced by the ATP synthase.
c) The oxygen is used during glycolysis to break down glucose. CO2 is produced as glucose is broken down.
d) The CO2 is used during electron transport as a final electron acceptor. Oxygen is produced during the citric acid cycle.

a tetrad is the foursome during meiosis made by two homologous chromosomes that have each already replicated into a pair of sister chromatids.

1. loamy sand is about 80% sand with 10% clay and defined mostly by sand particles with some clay to provide structure and fertility. the sand particles are easily visible and the soil holds structure but breaks apart easily.

2. scott sand can improve his soil quality by incorporating more silt and organic matter into the soil. peat moss and organic matter can also be incorporated.

some fungi obtain their nutrients from a living host (plant or animal) and are called most biotrophic fungi have fairly narrow host ranges—they are specialized on a limited called rhizomorphs that allow the fungus to grow from one tree to another. ascospores are formed inside a sac-like structure called an ascus. so your answer is a