1. biodiversity frozen layer of soil below the earth's surface
2. biome
number of plants and animals in an ecosystem
3. estuary
transitional area between land and water systems that support aquatic life
4. permafrost
similar ecosystems, such as marine or desert
5. wetlands
place where fresh and salt water meet

I'm pretty sure there's a geometry rule for   anyways, if the triangle is equilateral, and the circle is circumscribed, the circle is outside of the triangle.  to find the area, you need the radius.  the radius should be a straight line from the center of the triangle to any of it's points.  draw lines from the center of the circle to each of the triangle points.  draw three more lines from the center to the middle of the sides of the triangle.  you should now have six separate 30-60-90 triangles inside of your original triangle. use your 30-60-90 rules to solve for the radius, then the circumference. 

C.about 10% i think

Answerbecause of improved transportation, communication, and other advantages;

Just try your best buddy