Number the steps for balancing equations:

use coefficients to increase the atoms on each side.

check to make sure you have the same number of each type of atom on each side.

count the atoms on each side.

identify the atoms on each side.

answer: land bridge theory. land bridge theory held that shifting portions of dry land explained the finding of identical species on different continents. plate tectonic theory eventually eliminated the land bridge theory.

it is called the mitotic spindle