The number of known elements changed very rapidly over a 150-year period. There were 62 known elements in the mid-1800s. How many known elements
(total) are there today?
A.98 b.111 C.118 D.125

fsfd

step-by-step explanation:

fdddff

answer: f = 32.2m

step-by-step explanation: that is the answer

- "runner b is moving at a slower rate."

- "the graphs shown are graphs of distance(km) against time(min).

the slopes of this graphs are are given by:

slope = (change in y)/(change in x)

= (change in distance)/(change in time)

this is the formula for finding the speed. so, the slope of these graphs represent the speed of the runner.

taking each division in the graph to represent 1 on both axis:

runner a ⇒ speed = (2-0)/(1-0)

= 2/1

= 2 km/min

runner b ⇒ speed = (3-0)/(3-0)

= 3/3

= 1 km/min

this shows that   runner b is moving at a slower rate."