Answer:
Internal and external regulators are two types of proteins that regulate the cell cycle. Internal regulators allow the cell cycle to proceed only after certain events occur. External regulators speed up or slow down the cell cycle.
Explanation:
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I believe that elevated serum creatinine levels indicate a kidney disease
Answer:
The mentioned characteristics of variability are witnessed because of the phenomenon known as X chromosome inactivation in heterozygous females. As females possess two X chromosomes, they actually should not possess any color blindness.
The phenomenon of X-chromosome inactivation takes place in a random manner at the time of embryo development. During this only one X chromosome is inactivated. If the chromosome comprising the defective gene is inactivated, the individual will possess normal vision.
If the chromosome comprising the usual gene gets inactivated than the individual will be color blind. In the given case of female, X inactivation took place in one eye. The inactivation of normal alleles has taken place and thus she possesses normal vision with one eye and is color blind in the other eye.