Learn Russian: Это исследование описывает новые элементы.

You would use the present passive participle of описывать. Take the present tense stem описыва-, add the suffix -ем-, and the plural adjective ending -ые to match элементы. The agent (the research) takes the instrumental case, giving us: новые элементы, описываемые этим исследованием.

Why do новые элементы look exactly like the nominative case if they are the direct object of the verb?

Because элемент is an inanimate noun. In the plural, inanimate nouns (and their modifying adjectives) share the exact same form for both the nominative and accusative cases. If they were animate objects, the accusative would look like the genitive instead.

Описывает is the imperfective verb for "describes". Why must we use the imperfective aspect here?

In Russian, the present tense can only be formed using imperfective verbs. If you were to conjugate its perfective pair, описать (giving you опишет), it would automatically change the meaning to the future tense: "will describe".

The noun исследование (research) ends in -ние. What does this ending usually signify?

It signifies that it is a verbal noun, formed from the verb исследовать (to research / to investigate). Adding the suffix -ние is a very common way to turn a Russian verb into a neuter noun that represents the action or result of that verb, much like the "-tion" or "-ing" suffixes in English.