Question

When injury occurs why blood automatically clots?

Answer 1

Answer:

The blood automatically clots to prevent the loss of blood from the body.

Answer 2

Answer:

because due to the presence of platelets/thrombocytes here calcium ion is present that converts the prothrombin of plasma to thrombin again the thrombin in calcium ion converts the soluble fibrinogen into insoluble fibrin it makes a threads pf fibrin that mesh at the wound and stop blood flowing.