Which of the following is NOT the reason why the flowers in the laboratory open？
A. There was a clock in the laboratory.
B. They have a kind of "biological clock".
C. They have circadian cycles of activity.
D. Their "internal clock" tells them to open.
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Why may it happen in the future that people working in Europe will have to pay much higher
A. Because more and more children will be given birth.
Because they will earn more money.
C. Because they will have higher living standards.
D. Because the number of retired people will become even larger.
What happened to the flowers which were put in a laboratory in constant darkness？
A. They didn't open at all.
B. They opened as if they were in a normal garden.
C. They have circadian cycles of activity.
D. They died without knowing the time of day.
Which of the following is true according to the talk？
A. There has been a slower population growth in the past ten years.
B. The world's rate is higher than ten years ago.
C. Families are as large as before.
D. Birth control has been carried out well all over the world.
If you like children and you could offer a happy family to a homeless child, you may go to
A. Street Food
B. Night Shelter
Children't Home
D. Children's Hospice
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