not all the time
In "Himalayan mountains", the word "mountains" is not capitalized. It would be like saying "American mountains". It is NOT the same as saying the "Rocky Mountains", as "Rocky" is not a geographical area (and thus "mountains" should be capitalized). The Himalayas are.
No, coral does not need to be capitalized.
The word evolution does not need to be capitalized.
No, the word "revivalist" does not need to be capitalized unless it is at the beginning of a sentence or part of a proper noun.
No, the word "seismograph" does not need to be capitalized unless it is at the beginning of a sentence or part of a title.
No it does not need to be.
No, the word "motorcycles" does not need to be capitalized unless it is at the beginning of a sentence or part of a title.
No, the word "region" does not need to be capitalized in a sentence unless it is the first word of the sentence or part of a proper noun (e.g. "Pacific Northwest region").
No, the word "present" does not need to be capitalized unless it is at the beginning of a sentence or part of a title.
The word citizen does not need to be capitalized.
No.
Yes, "Cheerios" is a brand name and should be capitalized.