Is the THAT in the following sentence a conjunction?
There is strong evidence that Zika is spreading fast all over Brazil.
Is the THAT in the following sentence a conjunction?
There is strong evidence that Zika is spreading fast all over Brazil.
That can be the distal demonstrative determiner (contrasting with this, the proximal demonstrative determiner); it precedes noun phrases, and can act as a pronoun -- yes, I mean that (one).
That can also be a complementizer for tensed clauses of all sorts.
It appears in restrictive relative clauses where wh-words aren't used.
Relative clauses are adjective clauses; they modify nouns.
That also used to appear in adverb clauses, after the introductory conjunction, as in before that we set up the tent in the audio that's linked here. But that that occurs only in a few dialects nowadays.
Finally, the that-clause in the example sentence (There is strong evidence that Zika is spreading fast all over Brazil) is a complement clause modifying evidence. Complement clauses, which include that-clauses as one subtype, usually are subjects or objects of predicates, but in the example sentence it's a noun complement clause, a structure where a complement clause modifies a noun. This is only possible with a picture noun like evidence.
In this case, 'that' is a subordinating conjunction. The copula in '.. is spreading ..' is weakened from being stated as a fact, but it is linked to the other copula '.. is strong evidence'.