An extra copy of chromosome 21 in humans causes

Down syndrome

cystic fibrosis

HIV

none of the above

How do cells maintain water balance through osmosis? USATestPrep

1. Which of the following is a biotic factor? A. sunlight B. Worms C. water D. climate I think its B

Which of the following describes an old-growth forest? A. A forest that has been planted with pine trees to be harvested for paper production B. A Bristlecone pine forest that contains trees that are over 500 years old C.

How do water's relative densities as a solid and a liquid differ from that of most other substances

There is only one legitimate interpretation of the meaning of red shift data. True False

Which human activity has had the greatest impact on climate change? A. deforestation B. burning fossil fuels C. production of nuclear waste D. building skyscrapers

Check answers. 1. The active site A. Located in an enzyme (my answer) B. Is rich in amino acid C. Is located on a substrate D. A and B E. B and C 2. Anabolism is defined as the A. Sum of all chemical reactions B.

How are genetic characteristics associated with nonreproductive activities such as feeding affected by natural selection?

Smooth muscle is found in just one place in the body. true or false

Which of the following characteristics evolved independently in mammals and birds? A) bilateral symmetry B) amniotic eggs C) jaws D) bone E) endotherm