Humans _____atmospheric carbon dioxide concentration by a third since the Industrial Revolution began.

Deep sleep is important for everyone. The actual amount of sleep you need depends (23)_____ your age.

We stood on the bridge _____ the two halves of the city.

Studies reveal that food production will need to increase by 70 percent to _____the over 9 billion people on the Earth.

Mark the letter A, B, C, or D on your answer sheet to indicate the underlined part that needs correction in each of the following questions.

One of the (A) most important tasks (B) of parents is to teach (C) their kids to live independent (D).

He was frequently criticised for his self-centred attitude but was nonetheless very popular.

I believe (A) that disabilities should not to prevent(B) people from (C) participating fully (D) in our community's life.

What is the best title for the passage?