Water, a stable liquid, is formed when two flammable gases, hydrogen and oxygen, combine. What has happened? O An atom has been created.
O A compound has been created,
O A mixture has been created,
An element has been created

A compound has been created

Explanation:

Remember you cannot create an atom nor can you create an element so An atom has been created and An element has been created is incorrect. Also, a compound is something that is chemically bound and cannot be separated unless applied a chemical change, which is applicable to water. It cannot be a mixture since mixtures can be separated physically, which you can't do with water.

dogs is better and probably lizards.

after receiving a stimus, the sensory receptors send(s) signals to the appropriate area of the body.  

the must be sensory neurons.  

hope its .