How does the hydroelectric dam picture here impact the environment?

by releasing toxic chemicals in their emissions

by generating significant heat that artificially warms nearby water

by producing greenhouse gases

by blocking fish migration

By blocking fish migration

Explanation:

By releasing toxic chemicals in their emissions

 Hydroelectrics only emissions are usually, non harmful electromagnetic signals.

By generating Significant heat that artificially warms nearby water

  Possible, but they do not produce much significant heat

By producing greenhouse gases

   No, just no- its magnets that are water moved, no room for greenhouse gasses..

By blocking fish migration

It is a dam, blocking a river, with fish in it.

1.  The enzyme dicer cleaves dsRNA to form

small interfering RNA (siRNA).

2.  The siRNA binds to a special protein,  

which degrades one strand.

3. One strand of siRNA associates with the

protein to form an RNase complex.

4. The RNase complex binds to a specific

mRNA and degrades it.