Answer:
Step-by-step explanation:
I don't know how diatoms obtain their food, but I do know how algae obtains it. Algae is a plant, that green stuff you find growing on rocks in creeks and lake shores. Plants turn sunlight, water, and carbon dioxide into sugars, which it uses for food. Most plants also obtain nutrients from soil and water using their roots, but algae doesn't have roots so it only gets food through the process I explained above, photosynthesis. I hope this has been helpful.