Learn Finnish: Elinympäristössään yöllinen eläin naamioituu hyvin. - In its habitat, the nocturnal animal camouflages itself well.

The base is the compound word elinympäristö (habitat / living environment). First, we add the inessive case ending -ssä (in). Then, we add the 3rd-person possessive suffix (its). Because it follows a short vowel, this possessive suffix takes the form of lengthening that final vowel and adding -n, which turns -ssä into -ssään.

What is the difference between the verbs naamioitua and naamioida?

Naamioida means to camouflage something else. By using the -utua ending to make naamioitua, it becomes a reflexive verb, meaning the animal does the action to itself. This -utua / -ytyä suffix is a very common B2-level pattern for turning an action you do to an object into an action you do to yourself (or an automatic action).

How is the adjective yöllinen (nocturnal) formed?

It is built from the noun yö (night) by adding the suffix -llinen, which means 'pertaining to' or 'having the quality of'. You will recognize this same adjective-forming pattern in words like vaarallinen (dangerous, from vaara) and kirjallinen (written, from kirja).

Since we are currently learning about the ablative of respect, how could we add 'in terms of its color' to this sentence?