let's say you have "X VERBed", and you're wondering whether "VERBed" is a participle or a past-tense verb.

* if you can answer "did X VERB?" with a yes, then it's a past tense verb.

* if you can answer "did someone/something VERB X?" with a yes, then it's a past tense verb.

examples:

the speaker dedicated her speech to her late father
"did the speaker dedicate something?" --> yes
"did someone dedicate the speaker?" --> no
hence, past tense verb

the speech dedicated to Mr. Smith was very long
"did the speech dedicate something?" --> no
"did someone dedicate the speech?" --> yes
hence, participle

hope that helps

The bones of Majungatholus atopus, a meat-eating dinosaur that is a distant relative of
Tyrannosaurus rex and closely resembles South American predatory dinosaurs, have been
discovered in Madagascar.
(A) The bones of Majungatholus atopus, a meat-eating dinosaur that is a distant relative of
Tyrannosaurus rex and closely resembles South American predatory dinosaurs, have been
discovered in Madagascar.
(B) The bones of a meat-eating dinosaur, Majungatholus atopus, a distant relative of
Tyrannosaurus rex and with a close resemblance to South American predatory dinosaurs, has been discovered in Madagascar.
(C) In Madagascar, the bones of a meat-eating dinosaur, Majungatholus atopus, distantly related to Tyrannosaurus rex and closely resembled South American predatory dinosaurs, have been discovered.
(D) A distant relative of Tyrannosaurus rex, bearing a close resemblance to South American predatory dinosaurs is Majungatholus atopus, a meat-eating dinosaur, the bones of which have been discovered in Madagascar.
(E) A distant relative of Tyrannosaurus rex and closely resembling South American predatory dinosaurs, the bones of a meat-eating dinosaur, Majungatholus atopus, have been discovered in Madagascar.

THE OA is A, why not C?

Modifiers set within comma are not essential to the meaning of the sentence and can be struck off without hampering the meaning. Let's give C a thought on this

(C) In Madagascar, the bones of a meat-eating dinosaur, Majungatholus atopus, distantly related to Tyrannosaurus rex and closely resembled South American predatory dinosaurs, have been discovered.

C can be changed to a sentence written in bold without changing the meaning, but does it make sense ? NO

Therefore it could be struck off from probables

I am also wondering about the use of tenses:

How can a dinosaur, an extinct animal, resemble anyone (present simple)? I would say that past simple is a more logical choice.

Thanks

dave, your heart is in the right place -- that is to say, you've identified the correct type of error -- but you haven't classified the minutiae of that error correctly.

in the erroneous version that you cited, the first part is an adjective-style modifier (participle). however, the second part is actually a verb, so you've got a serious problem on your hands.
in other words, “resembled” would only make sense here as an actual verb, as in This dinosaur resembled that other dinosaur.

you can't put verbs in parallel to things that are not verbs, so there is your issue.