Plants and animals could not live without nitrogen<span>. It is an </span>important<span> part of many cells and processes such as amino acids, proteins, and even our DNA. It is also needed to make chlorophyll in plants, which plants use in photosynthesis to make their food and energy. hope this helps!</span>
They train our immune system so it's ready when our bodies are attacked, and they aid in digestion and supply us with vitamins. ... Scientists and doctors can even utilize prokaryotes to help the human body.
the is a definite article meaning that you cannot use it
"an" can only be used before words beginning with vowels
therefore the answer is" a"
Answer:roll it down a hill
Explanation:of you roll it down a hill the item builds energy