A. Bacteria because plants & animals can't obtain nitrogen directly from the atmosphere.
Answer:
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Answer:
Plants, by contrast, breathe through tiny pores called stomata on the underside of their leaves. These pores allow carbon dioxide to enter and oxygen to exit. Plants open and close their stomata in response to changes in their environment so they can get the CO2 they need, and avoid drying out.
Explanation:
THE ACTIN has the active site to which the heads of the thick filament will bind.
The muscle is made up of two major protein fibers, which are the actin and the myosin. Muscle contractions occur when myosin and actin slide over each other in a series of repetitive events. The protein actin has a thin structure and is abundant in eukaryotic cells while myosin is a thick filament.