A mutation is a change in trait. For example people who are lactose intolerant are normal, but people that can can drink milk without a problem have mutated. Hopefully this makes sense and helped.
the brain stem controls involuntary actions such as breathing, heart beating and blinking.
Filler Metal is a type of metal used in the fusion welding union, and it is necessary to produce a joint because it serves to collaborate in the opposition, to a greater or lesser degree, against the forces applied to it, without suffering deformation or breakage.
Answer:
They have a gizzard to grind the food.
Explanation:
Birds cannot chew since they have no teeth. However, the beak allows them to split very large seeds or swallow them directly.
For their digestion they have a stomach where digestion enzymes are released. Also they have a gizzard that is an organ that grinds the food mechanically. This gizzard usually has small stones inside that were previously ingested and that helps to digest the food.
