Historically, african elephants have had large ivory tusks. for many years, poachers (illegal hunters) have been killing elephants that have large tusks so they could sell the ivory, which is valuable. now, many african elephants have small tusks or do not develop tusks. which of the following is true?
a. the trait of tusk size in elephants has changed over time.
b. poaching has had no effect on the size of elephant tusks.
c. elephants without tusks are more likely to be hunted than elephants with large tusks.
d. elephants without tusks cannot reproduce.

The answer is letter A.

The trait of the tusks have changed over time because of the process of evolution. Adaptive evolution occurs when species need to survive and thrive in their environment. The use and disuse theory can defend this statement. Elephants developed tusks in able for them to engage in activities that are needed for defense mechanisms for larger predators. Since, they are among the biggest mammals that roam the Earth, the need for the tusks is slowly deteriorating. This is why some of the elephants develop small or do not really develop their tusks. 

B] nitrogen fixationmight be wrong, so correct me.want extra on your answers? just go on my account and go on questions and answer, or ask in the comments!