Sickle-cell disease is a recessive genetic disease. This means
A. at least one copy of each recessive allele must be present for each gene involved in sickle-cell disease in order for the disease to be expressed.
B. two copies of the recessive allele must be present in order for the disease to be expressed.
C. the environment can alter the expression of recessive genes, meaning any combination of alleles can cause the disease if the right environmental conditions are encountered.
D. only one copy of the recessive allele must be present in order for the disease to be expressed.
Answer: B
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John Tyndall demonstrated that microorganisms present in the air are carried on dust particles.
Answer the following statement true (T) or false (F)
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A. Hypothesis can be validated or invalidated while discovery-based research relies more on collection and analysis of data without a hypothesis B. Discovery-based science can be validated or invalidated while hypothesis based research relies more on collection and analysis of data C. There is only one type of experimental approach, both terms describe the same approach. D. Hypothesis-based research results in believable science while discovery-based research results in unreliable conclusions.
a. A
b. B c. C d. D Answer the question using the accompanying figure. In the box labeled ‘A’, ____ levels ____.
a. insulin; decrease b. insulin; increase c. glucagon; decrease d. glucagon; increase e. glycogen; decrease