What trophic level is highlighted in the food chain? sun → tree → insect → frog

The correct answer is TERTIARY CONSUMER.
Trophic level of an organism refers to the position that an organism occupies in a particular food chain. Organisms are placed in different positions in the trophic level based on their feeding behavior. The following trophic level exist: producer, primary consumer, secondary consumers and tertiary consumers. Primary consumer refers to the green plants, which produce food for themselves and all other living organisms. Organisms that feed on green plants are called primary consumers, e.g insects such as grasshopper. An organism that feed on primary consumer is called secondary consumer, e.g toad, which feed on insects. A tertiary consumer refers to an organism that feed on a secondary consumer, e.g snake feed on toad.

I would believe tertiary consumer...I'm learning about the same subject...Just...less complicated...

Label X is Nucleus ; Eukayotic cell ; Label W is Chloroplast  

Explanation:

The given image is a eukayotic cell as it has well defined nucleus and membrane bound cell organelles such as nucleus, mitochondria, chloroplast.

The label X is nucleus, It contains genetic material and it controls all the activities of the cell.  

The label W is chloroplast. It is a type of plastids which contains chlorophyll.  It prepares food for the plants through photosysnthesis.

Presence of chloroplast and cell wall shows that the image is of a typical plant cell.