Answer:
B. A sperm cell fertilizes a vertebrate's egg cell, creating a zygote.
Step-by-step explanation:
Not A, because it is showing asexual production, in which, when the pollen lands, it will grow without needing of an opposite gender.
Not C, because it is exactly the same as A, in which it promotes asexual production.
Not D, because while sexual reproduction is needed, it does not give the process, rather, the process of life after being borned (you want an answer that gives the process before birth.
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