How does mining affect local populations? a. mining is a vital part of the economy of surrounding towns. b. mining introduces pollution into local water supplies. c. mining disrupts local populations of flora and fauna. d. all of the above are true.

D

Explanation:

Mining is good for the local economy because:

Mining pollutes fresh water, by using water to process ore and other materials, the water is then discharged into the rivers.

Mining causes deforestation, soil contamination, as well as contamination of water. This results in the loss of biodiversity

organisms that lack symmetry are called asymmetrical and belong to phylum porifera/sponges.

organisms with specialized stinging cells belong to phylum cnidaria. stinging cells are called cnidoblast cells.

cnidarians show two morphological forms : polyp (sessile) and medusa (mobile)

filter feeding is observed in porifera members.  

alternation of generation is observed in coelenterata or cnidaria. there is alternation of asexual polyp form and sexual medusoid form. it is also referred as metagenesis.