When you have a skin cut, the released blood will usually thicken and form a scab. What is the role of the scab

When your skin is cut, scraped, or punctured, you usually start to bleed. Within minutes or even seconds, blood cells start to clump together and clot, protecting the wound and preventing further blood loss. These clots, which turn into scabs as they dry, are created by a type of blood cell called a platelet.

Explanation:

the contamination

we are putting to many trash.

it provides an alternative energy pathway for the reaction to proceed.

a catalyst is a substance that speeds up the rate of a chemical reaction but is not consumed during the course of the reaction.

catalysts increase the rate of reaction without being used up. they do this by lowering the activation energy needed. with a catalyst, more collisions result in a reaction, so the rate of reaction increases. different reactions need different catalysts.

a catalyst works by providing an alternative reaction pathway to the reaction product. the rate of the reaction is increased as this alternative route has a lower activation energy than the reaction route not mediated by the catalyst.