The letter that represents enzyme is B.
I believe it's B. BRCA1 and BRCA2.
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.
As you can see in the table presented below, all of the gametophytes have seeds do not form in an enclosed structure and <span>undergo alternation of generations (marked in purple)
The gingkos were widespread in the distant past, but are now presented with only one species with fan-like leaves, the Gingko Biloba. (green)
The gnetophytes have three genera with very different looking species. One of the most iconic ones being the Welwitschia mirabilis often called the wise man's beard. (blue)
The conifers include redwoods, like sequoias and all, have pines as leaves and produce cones. (brown)</span>