Well first i just wanna say that life on mars has been discovered,not little green men but Bactria found on the surface and small traces of water have been found as well. some forms of life need little water to survive (like bacteria) but they still need water so yes there is water on mars the question is will we find it.
The controlled experiments are performed by the scientists, when they want to study the changes in the sample on changing a single variable. So, the correct answer is option (b).
In case, all variables are kept same, no changes would be observed in the experiment sample. A controlled experiment can be performed on living thing as well as non living. But, controlled experiment cannot be performed on the things which are influenced by a lot of variables, as they cannot create realistic results. So, the option (a), (c), and (d) are incorrect.
Answer:
Water
Explanation:
Molecular oxygen is the terminal electron acceptor and serves to receive electrons from reduced NADH and FADH2 to reoxidize them. NADH and FADH2 are formed during glycolysis and Kreb's cycle. These reducing powers should be re-oxidized to enter in the first two steps of aerobic respiration again.
For the purpose, NADH, and FADH2 transfer their electrons to the molecular oxygen via electron transport chain. After accepting the electrons, molecular oxygen is oxidized into the water molecule. Therefore, radioactive oxygen isotope would appear in the form of a water molecule after completion of cellular respiration.