When do molecules "stop" moving into and out of the cell?

Lupus, a condition in which the body attacks its own cells, is an example of 1-an allergic disorder. 2-an immunodeficiency disorder. 3-a cancer of the immune system. 4-an autoimmune disorder.

Some scientists have proposed that the earliest forms of life may have existed in an "RNA World" where RNA was both the genetic material and responsible for enzymatic activity. Imagine that you have recreated such a life form.

A woman is married for a 2nd time. Her first husband was blood type A and her son by that marriage was type O. Her new husband is type B and their child is type AB. What is the woman's blood type and genotype?

Which of the following is an organism whose cells do not have a membrane bound nucleus

Which of the following statements about introduction is false? Many introduced organisms out-compete natives for food and shelter. Often there is not a natural predator of an introduced organism, which allows them to flourish.

Early microbial ecologists knew that hydrogen gas is oxidized in soil and that ammonia is oxidized in sewage. How did these scientists determine that microbes are responsible for these ecological reactions? Choose one: A.

If more genes for less arm hair are passed on more frequently after several generations will people have more or less arm hair?

What kind of tissue is the precursor of long bones in the fetal skeleton?

Why are old rocks rare on the ocean floor

What is a storage form of carbohydrate energy?