Why was the reduction of the bison population to under 1,000 individuals a bottleneck event for the species? a. It drastically reduced the gene pool of the species. b. It reduced the territorial range available to the species. c. Foreign genes were introduced by crossbreeding with cattle. d. It reduced the prevalence of recessive traits.

The correct answer is - option A.  It drastically reduced the gene pool of the species.

Explanation:

A population bottleneck is a process that definitely decreases the size of a population. The bottleneck might be brought about by different occasions, for example, an ecological disaster, the hunting of animal groups to the point of elimination or extinction, or territory obliteration that outcomes in the deaths of creatures.  

Bottleneck occasions are named because of the extraordinary loss of genetic diversity. In spite of the fact that this can now and then bamboozle because of certain species colossal contrasts between the genuine populace and compelling populace.

they deliver oxygen to the blood

it would affect precipitation by causing flooding in some areas of the world due to climate increasing, causing the glaciers in the northern and southern pole of our planet to melt.

i wish you would have provided choices to simplify it and allow me to give an exact answer.