Answer:
Some plants, such as roses, have thorns on their stems or branches. These act as A. To stop animals from eating the stems.
B. Exchanged during normal breathing
That would be (A.) they are prokaryotic cells. If you want to see nucleus, look under a compound microscope. Hope it helps!
30.) A calorie is a unit of energy.
31.) A reflex causes an organism to respond to a sudden change.
32.) Respiration removes carbon dioxide from the air and into your lungs.
33.) Wind is a renewable source of energy.
34.) A chemical reaction because it is burning and releasing heat.
35.) Not sure, but I think it's volume.
36.) A decrease in food would cause the merlins to decrease as well.
I think it C i hope u make a 100 i trying my best