Answer:
They can be different declensions.
Explanation:
A declension is simply the "family" that a noun belongs to - for example, the noun lex, legis<em> </em>(law) is part of the 3rd declension and the noun portus, portūs (harbor) is part of the 4th declension. There is no rule in Latin that all the nouns in a sentence have to be part of the same declension.
Answer:
Depends on how much you want to learn really, schools usually just make you learn all sorts of parts of the subject. Some that could be necessities and some that you would rarely use.
Explanation:
I agree too. I’m pretty sure the answer is the first one which is equipment.
