NEED ASAP! Why do geologists think earths core contains mostly iron?

A. Other orbiting bodies contain more iron than earth's crust does.
B. The moon's crust contains far less iron than earth's crust.
C. The crust contains no nickel.
D. The crust contains a mixture of iron and silicon.

Which plains area lies in both the united states and canada? altiplano central canadian shield coastal plains great plains

Why do leaves change color in the fall? green pigments break down and no longer mask the color of chlorophyll. chlorophyll breaks down and no longer masks the colors of other pigments. red- and yellow-colored pigments grow and mask green-colored chlorophyll. green-colored chlorophyll breaks down and turns red and yellow.

Can bacteria reproduce in a way such that when you start out with two bacteria, you get five bacteria? why or why not? * a. yes, because bacteria reproduce sexually, and can produce any number of offspring, just as humans do. b. no, because bacteria grow at an exponential rate. c. no, because when bacteria reproduce, they split into two parts, and two bacteria splitting would result in four bacteria.