I believe the answer is C. They are a type of jelly fish.
Holmes said to Watson "My dear doctor, this is a time for observation, not talk, because it was part of his method to observe closely and then to consider his observations. The correct answer is A.
I'm not sure what you mean by "compartments", but the cardiovascular system consists of the heart, blood vessels, and approximately 5 liters of blood.
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!
