Let's look at the sentence: "Koalas sleep most of the day and eats eucalyptus leaves."
There is a small grammar mistake here. The word "koalas" is plural (more than one koala), so the verbs (actions) that talk about what koalas do should match and be in plural form too.
In this sentence, "sleep" is correct because it matches the plural subject "koalas." But "eats" is singular (used for he, she, it), so we need to change it to "eat" to agree with "koalas."
So, the correct sentence is: "Koalas sleep most of the day and eat eucalyptus leaves."
This way, both actions match the plural subject "koalas."