In one kind of abnormal chromosome inheritance called down syndrome, a child has three copies of

a. chromosome x.

b. chromosome 21.

c. chromosome y.

d. chromosome 23.

What is a main cause of reduction in bird populations? A. Land development B. Overfishing C. Increased insect populations D. Stolen bird eggs

What is the effect of molecule size on a molecule size on a semipermeable membmane?

Although outer space can be extremely cold spacecraft must also be able to release excess heat different parts of a spacecraft may need to be heated or cooled in different situations since outerspace is there perfect vacuum the main way that he is

1. Which one lived in Antarctica earlier, the labyrinthodont, the lystrosaurus, or the duck-billed dinosaur? Explain.

Which of these outcomes is a negative impact of pastoral societies on the environment? O A. Overgrazing O B. Nomadic ways O C. Overpopulation O D. Resource renewal

Which statement about crustaceans is true? * (A) all have the same number of appendages (B) all have an internal skeleton (C) all have an exoskeleton (D) only some have jointed appendages

5. The measurement of the amount of friction a surface will generate is called the of friction'.

How much of earth's air is made of Nitrogen?

If a normal cell divides, you can assume that a. its surface area has become larger than its volume. b. its volume has become larger than its surface area. c. it has grown to its full size. d. it has grown too large to meet its needs.

What type of isolation occurs when species mate at different times of the year?