A student is collecting the gas given off from a plant in bright sunlight at a temperature of 27°C. Which gas is the plant producing.. a
oxygen
b
nitrogen
c
carbon dioxide
d
hydrogen

Which best describes red blood cells? a. they are colorless b. they protect against disease-carrying microorganisms c. they transport oxygen throughout the body d. they aid in blood clotting

The diagram shows the layers of earth. convection currents in which region influence the movement of tectonic plates

What did not occur in the proterozoic eon a)the oxygen levels increase greatly in the atmosphere, b)the emergence of the eukarya , c)muti cella’s eukaryotic organisms began to diversify, d)anaerobic bacteria kept thriving with more oxygen