All of the following are common types of pain stimuli except a. visual b. mechanical c. chemical d. thermal

The answer is A). Visual 

Answer: Option A visual

Explanation:

Pain is stimulated via the pain receptors which are present everywhere in the body.The stimulation perceived by the pain receptors is transferred to the brain by specialised nerves via the spinal cord.These pain receptors are nothing but free nerve endings and there are mainly three types of pain receptor stimuli:

1. Mechanical - A mechanical stimulus is perceived by actions such as stretching or application of high pressure.

2. Thermal - A thermal pain stimulus is generated due to temperature changes such as extreme heat or cold.

3. Chemical - A chemical pain stimulus is generated by chemicals such as acids which are applied eternally or by chemicals produced inside the body such as serotonins, bradykinin etc.

As, the pain stimuli are only of three types - mechanical, chemical and thermal, we can conclude that there is no visual stimuli for pain.

Although i don't know what is the simulated system, starfish are predators that eat mostly  microalgae,  snails, sponges, bivalves, mussels and other small marine animals. removing starfish from any system would definitely increase this animals that they prey.

Yes yes yes very good