Problem: John wanted to know what makes a lake different from a pond. To that end, he first visited a lake. He labeled that part of the study as case A. Then he visited a pond. He labeled that part of the study as case B. John realized that though both of them were water-bodies, they were very different. Which water-body would be deeper, case A or case B?

A: case A

Problem: John is a marine biologist. He was collecting samples from six locations in the ocean, location A, location B, location C, location D, location E, and location F. Location A was near the shore, but location B was farther offshore. Location C was in shallow water, but location D was deeper into the ocean. Location E was a habitat with very few organisms, but location F was a habitat full of organisms. Which location would see less viruses, location C or location D?

A: location D

Problem: The Danube and Volga rivers both form large deltas, but the Danube river delta is larger and grows faster every year. Which river experiences a less significant decrease in flow velocity when it reaches the sea?

A: Volga

Problem: In his chemistry lab David is learning about acids. He took three solutions to identify them correctly, sample A, sample B, and sample C. Sample A is a strong acid; sample B is a weak acid; and sample C is not an acid. David needs to identify the content of each sample by learning about their attributes. Which sample would most likely damage materials, sample A or sample B?

A:
sample A