will almost always enable the surveyor to eliminate angle measuring mistakes. Measuring angles several times with the telescope in its normal position and in its reversed position and averaging the results will result in improved precision.

A theodolite

Step-by-step explanation:

theodolite is a precision instrument that is used to measure the angle in the horizontal and vertical planes and it is the most commonly used in surveying.

A modern developed theodolite consists of a movable telescope that is mounted within two perpendicular axes called the horizontal axis and the vertical axis. Pointing the telescope on a target object will enable measurement of angle with great precision.

add 5 subtract 1

step-by-step explanation:

i'm assuming that it's c.)   volcanoes built the mountains and earthquakes tore them down.