Listen and answer questions 21–30.
Complete the sentences below.
Write NO MORE THAN TWO WORDS for each answer.
The students initially thought that vertical farms were primarily limited by high .
Dr. Patel points out that a major overlooked problem is the lack of in sealed environments.
Chloe was surprised to learn that urban farming can actually lead to an increase in local .
Sam argues that the most significant advantage of hydroponics is the drastic reduction in the use of .
The tutor advises the students to restrict their project focus exclusively to .
Complete the flow-chart below.
