C . Record the time to complete a chemical reaction
Answer:ball, ramp, and angle
Explanation: these are the three things that are controls because you can control them
(a) The distance of the image formed by the concave mirror is 19.1 cm.
(b) The image formed is diminished and real.
<h3>
Image distance </h3>
The distance of the image formed by the concave mirror is calculated as follows;
1/f = 1/v + 1/u
1/v = 1/f - 1/u
1/v = 1/15 - 1/70
1/v = 0.05238
v = 1/0.05238
v = 19.1 cm
The image distance is smaller than object distance, thus the image formed is diminished and real.
Learn more about concave mirror here: brainly.com/question/13164847
#SPJ1
A). Archaea Hope it helps you
Answer:
The people with caculators will probably answer faster due to thier ablitiy to use a device of technology
