18. What processes have caused Earth's surface to change over time? a. tectonic plate movement
C. A&B
b. weathering and erosion
d. none of the above

Three point charges, two positive and one negative, each having a magnitude of 20 μc are placed at the vertices of an equilateral triangle (30 cm on a side). what is the magnitude of the electrostatic force on the negative charge

Avalue that describes how heavy an object is and is related to the force of gravity is

Write the function getkthdigit(n, k) that takes a possibly-negative int n and a non-negative int k, and returns the kth digit of n, starting from 0, counting from the right