In a study of the shore crab *Carcinus aestuarii* in coastal estuaries, marine biologist Dr. Kenji Sato investigated the relationship between tide cycles and feeding behavior. Sato hypothesized that these crabs forage more actively during high tide than during low tide because the deeper water provides cover from predatory birds. Which finding, if true, would most directly support Sato's hypothesis?
- AThe crabs consumed a wider variety of prey species in the estuary than did crabs of the same species living in deep ocean reefs.
- BPredatory birds in the estuary were observed catching more crabs during high tide than during low tide.
- The crabs spent significantly more time foraging in the open during high tide, when predatory birds were less successful at spotting them under the deep water, compared to during low tide.Answer
- DThe crabs will likely migrate to deeper offshore waters if the population of predatory birds in the estuary increases.
Answer
The crabs spent significantly more time foraging in the open during high tide, when predatory birds were less successful at spotting them under the deep water, compared to during low tide.
The correct answer provides direct evidence supporting the biologist's hypothesis. It shows that the crabs forage more in open areas during high tide and links this behavior to the reduced hunting success of predatory birds in deeper water, directly reinforcing the claim that high tide provides protective cover.
Step-by-Step Solution
Key Concept
Command of Evidence: Textual
Estimated Time:1m 0s