Subtropical waters are typically more saline than equatorial waters because of the bigger temperature and much lower precipitation.
The precipitation manages to lower the salinity on the surface of the water even create ''pools'' with fresh water in the middle of the saline water. In the equatorial region there's rain almost every day, so the salinity is lower, while in the subtropical regions there's seasonal rain and it is in much lower amount, the temperature is higher which makes the water evaporate more and the salt to be more concentrated, thus the higher salinity.
'Climatic variations' and 'Human activities' can be regarded as the two main causes of desertification. removal of the natural vegetation cover（by taking too much fuel wood）, agricultural activities in the vulnerable ecosystems of arid and semi-arid areas, which are thus strained beyond their capacity.
Answer:
to provide a reference system
Explanation:
The equator and prim meridian used on maps provides a reference system for determining location and navigating the earth.
- An equator is the only line of latitude that is a great circle.
- Prime meridian is a line of longitude that is 0°
- When both are used, they can form the basis of a reference system to determine places on earth.
- Using these lines, we can assign values of coordinates to the earth surface to facilitate location determination.
The equator and prime meridian are used on maps to provide a reference system.
Answer: The Rocky Mountains
Explanation:
It is the mountain range that divides the west coast of the USA and Canada from the rest of the countries.
