Self-study
After 1950, in response to record growth in worldwide food demand, farmers worldwide sharply increased fertilizer use. ██ █ ███████ ███ ████████████ ██ ████████ ████ ████ ███████ ██ █████ █████ █████ ███████ ████ ██████ ██ ████████ ████████ ████████████ ████ ████████ █████████████ █████████ ██████████ ███ ███ ████████ ██ █ ███████ ███████ ████ ███ ███ ████████
"Surprising" Phenomenon
Fertilizer was very effective at increasing farmland productivity in the past. Given that farmers want to increase productivity even more, why has the use of fertilizer declined slightly in recent years?
Objective
The correct answer must explain why farmers seeking to increase productivity have reduced their use of fertilizer, despite it having been very effective in the past. It’s likely that something has changed since 1985 that either reduced fertilizer's effectiveness or farmers’ ability to use it.
5.
Which one of the following, ██ █████ ████ █████ ██ ███████ ███ ████████ ███████████ ██ ███ ███████████ ██████
a
Since 1985 the ████ ██ █████ ███ ███████ ██████████ ███ █████████ ███ ████████ ███ ████ ██ █████ ███ ██████ ████ ███ ████ ███████ ███████ ██████████ ███ █████ ████████
A relative shortage of available farmland would create an even greater need to use land efficiently. Also, the stimulus already establishes that farmers seek to increase productivity. This makes the reduction in the use of fertilizer even more confusing.
b
Several varieties of ████ ██████ ████ ████ ██████ ███████ █████████ ████ ██ █████████ ███ ██ ██████████ ██ ██████████ ██ ███ ███████████ █████ ██████
So we're growing some new crops, but this tells us that fertilizer is just as effective on the new crops. That doesn't give us any reason why fertilizer isn’t used as much today.
c
Between 1950 and ████ ███████ ████ ████ ██ ████████ ███ █████ ██ ████ █████████ ██ ████ ███████
The stimulus already establishes that fertilizer led to a massive increase in farmland productivity. Given that fact, why did farmers reduce their use of fertilizer in the following years? This doesn't tell us.
d
After fertilizer has ████ █████ ██ ████ ███ ███████ ██████ ██████ ██████████ ██ ███ ████ ██ ██████████ █████ ████ ███ █████████████ ███████ ████ ███████████
This gives us reason to believe that fertilizer’s effectiveness plateaus at a certain point, which explains why farmers decreased their use of it over the years. Why spend money on fertilizer that is now ineffective?
e
Between 1975 and ████ ██████████ ██████ ███████████ █████████ ███████ ██ █████ ████████ ██ ███████ ████████████████████ ████████ ███ █████ ████████ █████████ █████████ ██████████ ███████████
The correct answer must explain why fertilizer use declined after 1985. Factors influencing fertilizer production before that time are irrelevant, so this isn't helpful.