Which sphere is not a part of the cycling of oxygen through earths systems

Asnail, elodea (aquatic plant), or both were added to the tubes and they were stoppered. tubes were placed under a grow light for 24 hours and the results recorded. the test tubes were then covered for 24 hours to produce a dark environment and the results recorded. which statement best explains the change in test tube d from the light setup to the dark setup.

How does natural selection change thephenotypes within a population over time?

Asap what occurs after cytokinesis is completed at the end of meiosis 1?