The centrosome is: A. a region of the chromosome where microtubules attach to chromosomes during mitosis.
B. the microtubule organizing center for the mitotic spindle.
C. a region of the chromosome where sister chromatids are attached to each other.
D. a region of the chromosome where kinetochores attach.

The steps in the formation of extrusive igneous rocks are listed below in an incorrect order: 1. rock melts due to high temperature. 2. rock is buried deep under earth's surface. 3. magma is forced out of earth's surface during volcanic eruption. 4. lava cools and crystallizes to igneous rock. which of these best shows the correct order of steps in the formation of extrusive igneous rocks? 1, 3, 4, 2 2, 1, 3, 4 3, 4, 2, 1 4, 2, 1, 3