Question

Huge amount of toxic chemicals leak into the surrounding eco system because of
(a) industries (b) mining (c) pestisides (d) modern technology

Answer 1

Industries because mainly the toxic chemicals are released by industries and released in to environment without treatment. which leads to ecosystem degredation.
other options are also correct because each of these leads to ecosystem degredation but I think mainly industries leads to toxicity in environment.
I hope it will help you.