What do you mean but if you mean what I think you mean then you take half of the tadpoles
Its protons because we know electrons= protons so its postive so a)
excretory system: removes waste from blood.
respiratory system: obtains oxygen so the energy in the nutrients can be extracted.
circulatory system: transports nutrients from small intestine to the othet tissues.
nervous system: regulates and controls digestive functioning.
( Am not completly sure, but i think this is the answer)
When we breathe in, oxygen enters our lungs and enters small sacs in our lungs called the alveoli. In the alveoli, the oxygen diffuses INTO the bloodstream through small blood vessels, called capillaries, that surround these alveoli. The oxygen is now in our bloodstream instead of our lungs and is used in cell respiration etc.
Oppositely, carbon dioxide is diffused FROM the bloodstream TO the alveoli, also through these capillaries. The carbon dioxide is now in the lungs instead of the bloodstream and when you breathe out, the carbon dioxide is breathed out out of your lungs.
Hope this helped, even if it helped a tiny bit. :)
Answer:
most common samples used today Blood and Hair
