Huygens was writing about the theory of light.
Answer:
Amoebozoa
Explanation
Amoebozoa is a major taxonomic group containing about 2,400 described species of amoeboid protists,
Answer: It would probably be A.
Explanation: Abrasion means scraping or wearing away. Therefore the correct sample is probably going to look smaller, smoother, and more even from all the scraping of the river currents.
Hope that helps!