Answer:
Algal blooms occur when algae multiply very quickly. Blooms can form in waters that are rich in the nutrients the algae need to grow, such as nitrogen, phosphorous, and iron. ... Blooms may become more frequent as the earth warms and the levels of nutrients in our waters increase.
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"
(Pp)(Yy) —> PY, Py, pY, py
