(2) Producer?

(3) Answer

(4)A and b?

(5) lack of oxygen (answer that too much carbon dioxide leads to too low pH, shrimp is preyed by small fish, shrimp lacks food, its environmental carrying capacity is limited, and its competitiveness is weak)

Test analysis: Fish is the largest number of vertebrates, so small fish are vertebrates. Producers, including all green plants and some bacteria, are the most basic components of the ecosystem. They are autotrophs that use simple inorganic substances to make organic matter, so aquatic plants are the producers of the most basic components in the food chain. In A, only aquatic plants carry out photosynthesis, and the water body has not changed, so the PH value remains at 7. The fourth question, C and D, are not optional because they only observe the relationship between aquatic plants and shrimp.

Comments: Students should understand the importance of producers in the ecological environment, which is also the lowest but most basic part of the whole food chain. To do such a topic, we need to master every related link of the ecosystem.