In which of these systems can parts of the oxygen cycle be found?

a. atmosphere
b. biosphere
c. geosphere
d. hydrosphere

The oxygen cycle can be found in all but the geosphere. There's oxygen in the atmosphere, so it has to be there, and the biosphere includes living things, which breathe oxygen, and water (hydrosphere) is made up of partly hydrogen, so there has to be oxygen there as well.

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

the must be sensory neurons.  

hope its .