The underlined word <em>and </em>is a conjunction.
Conjunctions are used to connect words and sentences, and in this case, <em>and </em>connects <em>unicyclists and bicyclists. </em>
This is not an independent clause: it is dependent on the main phrase here, which is "<span>Most of these animals stay under water".
The underlined clause tells us something about why they must stay under water; and sentences that tell us about the why are called the "adverb clauses" - the correct answer.
</span>
Rukmani's struggle to feed her family during the drought is an example of an external conflict.
