I. The adrenal medulla does not regenerate, but when the inner two zones of the cortex are removed, a new ZF and ZR regenerate from glomerular cells attached to the capsule.

II. Immediately after hypophysectomy, the ZF and ZR begin to atrophy, whereas the ZG is unchanged because of the action of angiotensin II on this zone. 

III. The ability to secrete aldosterone and conserve Na+ is normal for some time after hypophysectomy, but in longstanding hypopituitarism, aldosterone deficiency may develop, apparently because of the absence of a pituitary factor that maintains the responsiveness of the zona glomerulosa. 

#Question id: 12097

#Unit 10. Ecological Principles

The herbaceous plant Achillea lanulosa is widespread in the Northern Hemisphere. Phenotypic variation in the species has been extensively studied along an altitudinal gradient from sea level to over 3,000 meters. In California there is conspicuous variation in  height; alpine plants are only several centimeters tall  while  those in  the San Joaquin Valley may reach a height of 1.8 meters. Adaptation to different local environments also results in variation in physiological processes such as photosynthetic rate, resistance to cold, and the timing of dormancy.

Which of the following methods would be best to determine whether the phenotypic variation in Achillea lanulosa is due to genotypic variation?

#Question id: 12098

#Unit 10. Ecological Principles

The herbaceous plant Achillea lanulosa is widespread in the Northern Hemisphere. Phenotypic variation in the species has been extensively studied along an altitudinal gradient from sea level to over 3,000 meters. In California there is conspicuous variation in  height; alpine plants are only several centimeters tall  while  those in  the San Joaquin Valley may reach a height of 1.8 meters. Adaptation to different local environments also results in variation in physiological processes such as photosynthetic rate, resistance to cold, and the timing of dormancy.

The morphological variation shown by Achillea lanulosa illustrates

#Question id: 24641

#Unit 10. Ecological Principles

#Question id: 24642

#Unit 10. Ecological Principles

 Which of the following is not the component of Soil?

#Question id: 24643

#Unit 10. Ecological Principles

 Which of the following statements about typical soil horizons is correct?

#Question id: 24644

#Unit 10. Ecological Principles

Which of the following layers is the zone of eluviation or maximum leaching?