Learn German: Die Forscher werden das riesige Skelett wohl gerade untersuchen. - The researchers are probably examining the huge skeleton right now.

This sentence uses the Futur I to express an assumption about something happening right now. In German, combining werden (will) with an infinitive and a particle like wohl (probably) is the standard way to express that you strongly suspect an action is currently taking place.

What is the purpose of wohl here?

The word wohl acts as a flavoring particle that translates to "probably" or "I suppose." It clarifies that the sentence is a present assumption rather than a future fact. Without it, Die Forscher werden das riesige Skelett untersuchen would simply mean "The researchers will examine the huge skeleton."

How does the sentence capture the English "-ing" form ("are examining")?

German does not have a continuous "-ing" verb form. To show that an action is happening in this exact moment, you just use a time adverb. Here, the word gerade (right now / at the moment) does the job of showing the action is currently ongoing.

Why does the adjective in das riesige Skelett end in -e instead of -es for a neuter noun?

Skelett is a neuter noun in the accusative case here. Because the definite article das already does the heavy lifting of showing the gender and case, the adjective gets the "weak" ending -e. If there were no article before it, it would need the strong ending: riesiges Skelett.