About 30 miles into Earth, the speed of seismic (earthquake) waves increases. What does this change
in speed indicate about the material through which the seismic waves are traveling?

The waves travel from rock into metal.

The waves are traveling from solid material into liquid material.

The waves are traveling from cooler material into hotter material.

The waves are traveling from less dense material into more dense material.

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

the must be sensory neurons.  

hope its .

oxygen +1 most likely

he movement of air through earth's or any planet's atmosphere is called wind, and the main cause of earth's winds is uneven heating by the sun. this uneven heating causes changes of atmospheric pressure, and winds blow from regions with high pressure to those with low pressure.

i hope this : )