I am not sure but I am guessing carbon and nitrogen :)
Some blood cells responsible for the transportation of oxygen and other are there for rebuilding of tissues. Fights things the body doesn't recognize
5. System level
6. Organ level
<span>The correct option is: IT HELPS CARRY AN IMPULSE BACK TO THE NEXT NEURON. There are two types of neurons, excitatory and inhibitoty neurons. Both serve to transmit impulse from one point to the other. Each neuron usually makes several connections with other cells.</span><span />
Answer:
Identifying elements in astronomical objects using their spectra. Measuring the spectrum of light from a star can tell astronomers what the star is made up of. Since each element emits or absorbs light only at a particular wavelength astronomers can identify what element are in the stars from the lines in their spectra.
