How is respiration controlled in humans?
What will be an ideal response?
Ventilation is normally controlled by respiratory centers in the brain, in the medulla oblongata. Respiratory centers in the medulla send a nervous message down to the intercostal muscles and the diaphragm causing them to contract, which results in inspiration. Expiration is a passive process when these muscles relax. Breathing rate is a response to the carbon dioxide levels in the blood (the blood pH is detected by chemoreceptors). During forced inspiration and expiration, the muscles contract more strongly, and other muscles of the chest wall are involved.
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Community ecology is best defined as the study of
A. plant distributions in a given region. B. mutual benefits between organisms at all scales in a region. C. the relationship between abiotic and biotic factors. D. how groups of species interact and form functional communities. E. global scale influences of major disturbances such as volcanos.
What enzyme is used to synthesize daughter strands of DNA during PCR?
A) replicase B) DNA polymerase C) RNA polymerase D) Taq polymerase
The punnet square is a useful tool for
A) determining the rate of segregation of alleles.
B) calculating how many mutations occur during DNA replication.
C) determining which genes or traits assort independently during gamete formation.
D) predicting the ratios of possible genotypes of a particular combination of alleles.
E) predicting the level of crossing over that will occur during meiosis.
If the concentration of sugar molecules in water on side "A" of a selectively permeable membrane is 5 percent, and the concentration of sugar molecules in water on side "B" of a selectively permeable membrane is 15 percent, which way will the water move and why?
a. The water will mostly move from side "B" to side "A" because the water concentration is higher on side "B." b. The water will mostly move from side "A" to side "B" because the water concentration is higher on side "A." c. The water will mostly move from side "A" to side "B" because the water concentration is higher on side "B." d. The water will not move at all because the water concentrations are isotonic.