If you dropped a ball from a height of 10 m and measured its distance to the ground every 0.1 s, what would the graph of position versus time look like?
a. it would curve upward.
b. it would curve downward.
c. it would be a straight line angled downward.
d. it would be a line parallel to the horizontal axis.

If you dropped a ball from any height, and measured its distance from the ground at any regular interval while it's falling, the graph of that distance versus time would be a graph that curves downward.

-- The ball is falling down.  As time goes on, it gets closer and closer to the ground.  Its remaining distance from the ground keeps decreasing, so the line on the graph slopes down.

-- The speed of the ball keeps increasing (it accelerates) because of the gravitational force on it. As time goes on, it covers more of the remaining distance during each interval than it did in the previous interval. The downward slope of the graph keeps increasing.

multiple allele inheritance is traits controlled by more than 2 alleles (ex: pigeons having 3 alleles of one gene govern their feather color).