The blood is collected in heparinized capillary tubes to prevent clotting. Heparin is a blood thinner and this anticoagulant is produced naturally by mast cells and basophils. But heparin can not dissolve or break the preformed clots.
It’s true, there are more insects than there are any other specie and more kinds
Non potable waters are not for drinking. It is not safe to be drink that's why drinking it can carry significant health risk on our body. Non potable waters are only for irrigation and other non drinking water activity. POtable waters are the water that is clean and safe to drink
Answer:
If I am correct it is when the weaker individuals or mutated individuals are killed of by other predators or by nature. Because they cannot survive this is natural selection because they are killed of by nature. Then if they are weak their species will go extinct, thus they are naturally selected to die and only the strong species remain.