Crop-growing Skyscrapers — IELTS Reading Answers

“The concept of indoor farming is not new, since hothouse production of tomatoes and other produce has been in vogue for some time.”

The gap needs the crop already grown indoors; the passage cites hothouse production of tomatoes, showing the concept of indoor farming is not new.

“Situated in the heart of urban centres, they would drastically reduce the amount of transportation required to bring food to consumers.”

The gap is the location where the farms would sit; being in the heart of urban centres would drastically cut the transport needed to reach consumers.

“Although the system would consume energy, it would return energy to the grid via methane generation from composting nonedible parts of plants.”

The gap needs what the system both consumes and returns; the passage says it would consume energy yet return energy to the grid via methane.

“It would also dramatically reduce fossil fuel use, by cutting out the need for tractors, ploughs and shipping.”

The gap is the resource whose use falls when tractors, ploughs and shipping are cut out; the passage names fossil fuel.

“A major drawback of vertical farming, however, is that the plants would require artificial light.”

The gap is an adjective describing the light plants would need indoors; the passage's major drawback is that they would require artificial light.

“One variation on vertical farming that has been developed is to grow plants in stacked trays that move on rails.”

The gap names the containers plants grow in for this variation; the passage says plants grow in stacked trays that move on rails.

“While it is possible that much of our food will be grown in skyscrapers in future, most experts currently believe it is far more likely that we will simply use the space available on urban rooftops.”

The gap is where most experts expect food to be grown; the passage points to the space available on urban rooftops rather than skyscrapers.

Methods for predicting the Earth’s population have recently changed.

“Applying the most conservative estimates to current demographic trends, the human population will increase by about three billion people by then.”

The passage applies the most conservative estimates to demographic trends but never says the methods of predicting population have recently changed.

Human beings are responsible for some of the destruction to food-producing land.

“Historically, some 15% of that has been laid waste by poor management practices.”

Poor management practices laying waste some 15 per cent of land are human actions, so people do cause some destruction of food-producing land.

The crops produced in vertical farms will depend on the season.

“For instance, crops would be produced all year round, as they would be kept in artificially controlled, optimum growing conditions.”

Crops would be produced all year round in artificially controlled, optimum growing conditions, so output is independent of season, the opposite of the claim.

Some damage to food crops is caused by climate change.

“However, more often than not now, due to a rapidly changing climate, that is not what happens.”

The phrase due to a rapidly changing climate explains why the expected growing conditions no longer hold, so climate change does damage food crops.

Fertilisers will be needed for certain crops in vertical farms.

“All the food could be grown organically, eliminating the need for herbicides, pesticides and fertilisers.”

Organic growing would eliminate the need for herbicides, pesticides and fertilisers altogether, not leave some crops still requiring fertiliser.

Vertical farming will make plants less likely to be affected by infectious diseases.

“The system would greatly reduce the incidence of many infectious diseases that are acquired at the agricultural interface.”

Greatly reducing the incidence of many infectious diseases means plants are less likely to be infected, matching the statement.