I guess the answer is B !! as it has no relevance and is not an observation !!
When the continents are at the Earths poles, they receive less sunlight.
Answer:
protein,carbohydrate,lipids,nucleic acid
The correct answer is "trans fatty acids".
Trans fatty acids (colloquially as trans fats) are a type of unsaturated fatty acids wherein instead having its double bonds in the cis configuration giving the fatty acid "kinks" in the molecules making it more soluble; the double bonds in trans fats are in the trans configuration (hence the name) and this will not give the molecule kinks making it less soluble. Less soluble trans fats are notorious in depositing in peripheral arteries as well as in coronary arteries that increase the risk for developing atherosclerosis.
Explore a wide variety of cells, from bacteria to human neurons, using a compound light microscope. Select a sample to study, then focus on the sample using the coarse and fine focus controls of the microscope. Compare the structures found in different cells, then perform tests to see if the sample is alive.