Self-study
The number of tornadoes recorded annually in North America has more than tripled since 1953. ███ ██████████████ ██████ ████ ███ ████████ ███████ █████████ ███ ████████ ██ █████████ ███ ██████████
"Surprising" Phenomenon
Why have there been so many recorded tornadoes since 1953 if the climate has not made them any more likely to form?
Objective
Any hypothesis resolving this discrepancy must state a reason for tornadoes to have tripled despite the constant climatic factors. It will explain why tornadoes since 1953 are much more likely to be seen or give a reason for the actual number of tornadoes to have tripled.
6.
Which one of the following, ██ █████ ████ █████ ██ ███████ ███ ████████ ███████████ █████████ ██████
a
The factors affecting ███ ████████ ██ █████████ ████ ███ ████ █████ ██ ██████████████ ██████ █████
This does not explain the increase in recorded tornadoes. Meteorologists know those factors have not changed since 1953, regardless of whether they understood those factors in 1953.
b
The intensity of ███ ███████ ███████ ██ ███████ ███ ████ ██ ███ ██ █████
This introduces a new mystery without resolving the discrepancy at hand. A greater average intensity does not explain a greater number of tornadoes.
c
The number of █████████ ████████ ████████ ███ █████████ ████ ████████ ██ ███ ████ ████ ██████
This offers no reason why the number of recorded tornadoes has tripled since 1953. It does not address the period between 1953 and five years ago.
d
The amount of ████████ ██████ ████ ██ █████████ ███ █████ █████████████ █████ █████
This does not explain why more tornadoes have been recorded since 1953. It is not stated that more tornadoes have destroyed property, only that the total damage caused by those tornadoes has been greater.
e
Many more citizens ███ ███████ ███████████ ██████ █████████ ███ ████ ██ █████
This explains why the number of tornadoes recorded has tripled since 1953. More people are looking for tornadoes, making them more likely to be spotted, even if their overall numbers have not changed.