I believe the answer is option <u>B</u>. but don't hold me to it. Hope it helps
Volcanoes affect people in many ways, some are good, some are not. Some of the bad ways are that houses, buildings, roads, and fields can get covered with ash. As long as you can get the ash off (especially if it is wet), your house may not collapse, but often the people leave because of the ash and are not around to continually clean off their roofs. If the ashfall is really heavy it can make it impossible to breathe.
Lava flows are almost always too slow to run over people, but they can certainly run over houses, roads, and any other structures.
Pyroclastic flows are mixtures of hot gas and ash, and they travel very quickly down the slopes of volcanoes. They are so hot and choking that if you are caught in one it will kill you. They are also so fast (100-200 km/hour) that you cannot out-run them. If a volcano that is known for producing pyroclastic flows is looking like it may erupt soon, the best thing is for you to leave before it does.
Some of the good ways that volcanoes affect people include producing spectacular scenery, and producing very rich soils for farming.
The right answer is He is studying oxygen, which can also be found in proteins.
Carbon atoms could also be a right answer if there was a statement...
Sugars, composed only of carbon atoms, hydrogen, and oxygen, are the simplest energetic nutrients. Example to (C6H12O6): If we look at the chemical formula for glucose, we can see that the proportion Hydrogen / Oxygen corresponds to that of water (H2O)
Lipids also consist of carbon atoms (C), hydrogen (H) and oxygen (O), but fatty acids are molecules that are low in oxygen. Example: Linoleic acid C18H32O2