It is necessary for the immune system to clearly distinguish foreign cells and proteins from those made by the body.

(a) Explain why this is the case:

(b) Name the type of disorder that results when this recognition system fails:

Which of the following statements is true? aWater and energy are not recycled in an ecosystem. bWeathering is the main way phosphorous is recycled. cThe total amount of energy in an ecosystem continuously increases.

What types of molecules are broken down to make ATP

What is the green pigment found in the chloroplasts of both plants and algae? A. Chlorophyll B. Protists C. Archegonium D. Bryophyte

How many chromosomes are in each daughter cell after mitosis?

What causes a valley breeze? O A. The difference in heating between altitudes O B. The difference in heating between land and sea O C. The sides of the valley heating more quickly than the air around it O D. The albedo of land

What is the genus of the popular fossils which are similar to "lucy"?

The parasympathetic division of the autonomic nervous system A. is associated with "fight or flight." B. opposes the effects of the sympathetic division. C. arises from parts of the spinal cord. D. uses the neurotransmitter norepinephrine.

Organisms which can make their own food are found in this kingdom:

What are hormones and why are they important?

What is the central dogma that tells how information is transformed to make a protein