Sentence Correction

This is an OG Question-

In virtually all types of tissue in every animal species, dioxin induces the production of enzymes that are the organism's trying to metabolize, or render harmless, the chemical that is irritating it.

OG says: This option is incorrect because the -ing form of a verb can be used as a noun (e.g., running is her favorite sport), but it is often awkward, particularly when used with a possessive, as in this case.

However, there is another OG Question where the right answer is:

The World Wild life Fund has declared that global warming, a phenomenon that most scientists agree is caused by human beings' burning of fossil fuels, will create havoc among migratory birds by altering the environment in ways harmful to their habitats.

Here we have -ing form of verb used with a possessive ("human beings' burning") but it's correct.

Can an expert please explain.

Check my two posts here:
https://www.beatthegmat.com/ing-form-t276835.html