Answer:
B AND D
HOPE ITS HELF FUL .........
Answer:
10⁴¹ s quark top lives have been in the history of the universe.
Explanation:
You need to determine how many quark top lives there have been in the history of the universe, that is, what is the age of the universe divided by the lifetime of a top quark. Expressed in a formula, this is:

Yo know that the "Age of the universe" is 100,000,000,000,000,000 which can also be expressed as 10¹⁷ s
.
You also know that the "Lifetime of a top quark" is 0.000000000000000000000001 which can also be expressed as 10⁻²⁴ s.
Then 
Recalling that the result of dividing two powers of the same base is another power with the same base where the exponent is the subtraction of the initial exponents, it is possible to calculate this division as follows:


<u><em>t=10⁴¹ s</em></u>
So <u><em>10⁴¹ s quark top lives have been in the history of the universe.</em></u>
Answer: 4m
Explanation:
Since the angle of incidence of a plane mirror can be anything from 0 to 90°
Assuming that the place is a perfectly square 4×4m room
The incident ray would be 45° for the choir(object) at a 4m distance, this is still within the range of values.
We do not forget also, that the focal length of a plane mirror is infinity, the organist would in fact see farther than 4m if need be. And wider