Mario sets up an experiment to determine the source of the oxygen gas produced by photosynthesis. To determine this, he uses an isotope of oxygen called O-18. He labels the O-18 oxygen so he can follow its path through photosynthesis. Plant A is given carbon dioxide that contains the O-18 isotope. Plant B is given water that contains the O-18 isotope. When he examines the oxygen from both plants, only plant B produced O-18 oxygen. This indicates that the source of oxygen is water. The photosynthesis involves the transfer of electrons between the photosystem I and II. The water gets split into oxygen, hydrogen ions and electrons in the photosystem I. The electrons move to the photosystem II where the carbon fixation into sugars takes place. The plant A will have O-18 isotope in its synthesised sugar molecule, which gets stored inside it.
<span>Correct matches: chemicals with their descriptions.
1. abscisic acid ( is the hormone that regulates survival functions of a plant, such as the opening and closing of stomata)
2. auxins (chemicals produced in plants that are characterized by their ability to induce cell elongation and cell division in stems)
3. cytokinins (chemicals that helps plant cells divide)</span>
<span>4. ethylene (a hormone that promotes ripening of fruit or blooming of flowers) </span>
<span>5. gibberellins (chemicals produced by plants that stimulate stem elongation, seed germination, and flowering) </span>
I think it is B because a cladogram shows how species are related AND also shows the evolution between them.
B. Upwelling brings cold nutrient rich water to the surface and boosts aquatic life
