Which changes occur in the composition of the earth's layers from the core to the surface?
a.
the material is hotter and denser.
b.
the material is cooler and denser.
c.
the material is hotter and less dense.
d.
the material is cooler and less dense.

The correct answer would be B.  The material is cooler and denser.

As we move from the core to the crust of the earth, the temperature and pressure of the layer keep on decreasing.

For example, the temperature of the inner core is around 9000 to 13000° Fahrenheit. The temperature of the outer core is around 7200 to 9000° Fahrenheit.

Similarly, the pressure also decreases as we move from core to crust.

Consequently, the density of the material increases as they become solidified.

substitution is the answer in this case

bacteria could be both, harmful and to us. harmful bacteria could make us sick and probably even by getting the chances of getting a disease, but good bacteria fight it off with your immune system. there is always bacteria everywhere we go. we need to make sure to wash our hands after using the restroom, before eating, after eating, after petting an animal too. so you see, bacteria is everywhere and is harmful or . i hope this . : ) : ) : )