How many significant figures are in the measurement of 0.020 km?

a. 1 b. 2 c. 3 d. 4

select the best answer from the choices provided
took the test subject is environmental science answer is b. 2

Answer: Option b) 2

Explanation:

Significant figures are the digits which play a role in defining a measurement that is they carry some meaning. There are three essential rules to find out the significant figures in a given number:Rule 1: Non-zero digits such are always significant.Rule 2: The zeroes after a non-zero number in decimal are also significant. An example is if the number is 0.0500 then the zeroes after 5 are considered significant, however, the zeroes before 5 are not significant.Rule 3: The zeroes placed between any two significant digits are also considered as significant e.g in 202 the zero is significant.Therefore,  in the number 0.020 km, there are two significant digits, one is 2 and the other is the last zero placed after 2.

Humans can affect weathering and erosion in several ways.  humans cause  increases in acid rain and pollution, which increase the amount of  weathering  agents in the air and water, and then on land.for an easy answer: 1) acid rain2) pollution