Answer:
Fact: a thing that is known or proved to be true.
Hypothesis: a supposition or proposed explanation made on the basis of limited evidence as a starting point for further investigation.
Theory:a supposition or a system of ideas intended to explain something, especially one based on general principles independent of the thing to be explained.
Law: a statement of fact, deduced from observation, to the effect that a particular natural or scientific phenomenon always occurs if certain conditions are present.
Explanation:
Note: these are not my words, credits to google search.
Answer:
Plants. Some Bacteria. Algae. These 3 are the photosynthetic autotrophs..
Why the others don't fit:
Athropods are hetertrophs. Not all bacteria are autotrophs. Only some protists are autotrophs.
Thylakoids, which are chloroplasts in the mesophyll cells of a leaf