When atria (Blank) ,blood flows into the heart.
^What goes in the blank??^

"pump" or "beat"

Explanation:

im assuming. because in order to have blood flow to the heart, the atria needs to pump the blood in order for it to move

both male and female gametes are produced by meiosis of the germ cells. therefore, both male and female gametes are haploid. one male and one female gamete unite during the fertilization to form the diploid zygote. in seed bearing plants, pollen grain is the male gametophyte, which produces sperm cells.