If scientists examine a bone fragment of a wooly mammoth and find that the percentage of Carbon 14 is 12.5 percent of the amount that would have been present at death, how many half-lives will have passed and approximately how old is the bone fragment?

it is called the mitotic spindle

all these collisions do one thing, and that thing is explained in the last option. when dusst, rocks and ice collide, they harden and form giant layers of rocks or hard ice.

d)   to harden materials to form different parts of earth’s layers

hope it ,

bioteacher101