Definition: In this task, you need to write a topic word from the given fact. The topic word must have at least one word overlap with the given fact. The topic word often involves adding a new word from a related concept. In your topic word, use at least one word from the given fact. Topic words with two or more words work best.

Positive Example 1 -
Input: Fact: pesticides cause pollution.
Output: pollution harms.

Positive Example 2 -
Input: Fact: pesticides cause pollution.
Output: modern farming pesticide.

Negative Example 1 -
Input: Fact: pesticides cause pollution.
Output: computer harms.

Negative Example 2 -
Input: Fact: pesticides cause pollution.
Output: toopaste helps.

Now complete the following example -
Input: Fact: Algae play significant roles as producers in aquatic ecosystems.
Output: 


Output:
Algae.
algae nonvascular.
algae plants.
algae produce.
algae.
aquatic ecosystem ocean.
aquatic ecosystems.
ecosystems.