What prevents sperm cells from traveling the entire distance to the egg?

Which of the following statements about protists are true? a. they are typically found in moist environments. b. they are all unicellular. c. they have a nucleus. d. they are all multicellular.

Neeed now for 1. eye color is a polygenic trait. what is the possibility of getting a green (aabb) eyed child, if parent 1 has brown eyes (aabb) parent 2 has blue eyes (aabb) 2.albinism is a recessive trait. having normal pigment is the dominant trait. what is the possibility of having an albino child if parent 1 is heterozygous normal parent 2 is heterozygous normal 3.in rabbits black fur is dominant over white fur. what is the probability of getting a rabbit with black fur if parent 1 is heterozygous black parent 2 is homozygous white

Which line in the graph above best illustrates an effect of the carbon dioxide level in the blood on breathing rate before, during and after a period of exercise? 1.b,2.c,3.a,4.d