Question

who is the producer?
lettuce
greenfly
ladybird
thrush

Explanation:

In an ecosystem, producers are organisms that can make their own food through photosynthesis. Lettuce is a plant (a green - plant) and can perform photosynthesis. Greenfly is an insect (a primary consumer that feeds on plants), ladybird is a secondary consumer (feeds on insects like greenfly), and thrush is a tertiary consumer (may feed on ladybirds or other small animals).

Answer:

Lettuce.