What is the ozone layer made of?

The word “constrained” in paragraph 4 is closest in meaning to______.

According to the passage, who was the first person to use artificial refrigeration for a practical purpose?

What can be inferred from paragraph 1 about cold storage before the invention of artificial refrigeration?

The word "These" in paragraph 3 refers to

The word "rough"in the passage is closest in meaning to ___________.

According to the passage, the first refrigerated railcar used what material as a cooling agent?

The word “it” in paragraph 3 refers to______.

According to the passage, all of the following are true EXCEPT___________.

The writer learnt to sail ___________.

What is the main point the writer is trying to make in the last paragraph?

Beta blockers work on some physical and emotional symptoms because they ________.

How did Juliette Davidson benefit from the experience of her first job?

The word "ball" in paragraph 2 probably means _________.

According to the passage, the doers of education are _____.

What is the main reason that people developed methods of refrigeration?