A. Polar bear
B. Phytoplankton
C. Killer whale
D. Capelin
参考答案:
B
本题详细解析:
Explanation:
Heterotrophs are organisms that cannot produce their own food. They obtain organic nutrients by consuming other organic matter, such as plants, animals, fungi, or decomposing organic material. Polar bears (Choice A), killer whales (Choice C) and capelins (Choice D) are all heterotrophs, as can be seen on the food web.
The producer, or photoautotroph for this marine ecosystem is the phytoplankton (Choice B), which forms the food web base. Photoautotrophs have the pigment chlorophyll and can absorb sunlight energy for photosynthesis to produce organic molecules. Because there are no arrows pointing to phytoplankton, phytoplankton can be identified as an autotroph.
