Hi there,

Don't you think that b and c are both correct answers in the below-mentioned sentence?

Many official institutions doing research _______ with ethical issues with regard to experiments on humans.

a) are worried b) are bothered c) are concerned d) are connected

No, you'd say "bothered by" but "concerned with."

(Worried about, bothered by, concerned with, connected to)
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So what's the difference between "connected with" and "connected to"? thx
You're right, "connected" can take either.

A is connected to B would tend to mean a physical connection.
A is connected with B would tend to mean an association of some sort.