The suffix that means a substance or agent that produces or causes is

Give the adjective-forming suffix which can mean pertaining to, pertaining to inflammation, or can indicate a drug or agent. Give the suffix which has antineuritic, laryingitic and arthritic as examples.

Give the suffix form (be careful not to give the combining form) meaning poisonous.

Give the adjective-forming suffix which indicates pertaining to or located in.  Give the suffix which has analgesic, gastric and toxic as examples.

Give the suffix form (be careful not to give the combining form) meaning study, science, the study or science of.

Give the noun-forming suffix which can indicate an abnormal or diseased condition.  Give the suffix which has nephrosis, stenosis and neurosis as examples.