Question

why do tomato plants need to protect themselves?
vibrations from insects legs harm tomato plants.
other plants play deadly tricks on tomato plants.
caterpillars and other insects eat tomato plants.
cannibal tomato plants start eating one another.

(under the yuck! illustration and text:)
bugs chomp on their leaves. when this happens tomato plants can change the chemicals in their leaves to make them taste bad. if enough plants in the surrounding area taste gross, the caterpillars will stop eating the plants. instead, they become cannibals and start eating one another!

Explanation:

To determine why tomato plants need to protect themselves, we analyze the options. The text explains that when bugs (like caterpillars) eat tomato leaves, tomato plants change leaf chemicals to taste bad. If enough plants do this, caterpillars stop eating them and may become cannibals. Among the options, "Caterpillars and other insects eat tomato plants" is the reason they need protection (as insects eating them prompts defense mechanisms). Other options: vibrations harming plants isn't the trigger for self - protection, other plants’ tricks on tomatoes isn't the main threat here, and cannibal tomato plants eating each other isn't about self - protection from external threats (the question is about why they need to protect from insects, etc.).

Answer:

Caterpillars and other insects eat tomato plants.