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.

the correct answer is - d. china has a large and growing population.

the fact that china has a large (the biggest) population, and it is still growing, doesn't hinder the agriculture production in the country. in fact, it can for increased production in the agriculture, since there's more labor force, as well the sheer mass of people produces lots of scientists that come up with new inventions as to how to improve this sector. nice example is the inner mongolia region in china, in general dominated by the gobi desert, but few scientist came up with a nice idea as to how to make the region productive by using plants that are very resistant to droughts, so lots of people have been employed, and the region is becoming greener and greener each year, and the production of food in this region is also increasing.

the answer is d p: cell, q: organ, r: organ system, s: tissue