<span>Without variation, there is no difference between members of a population to be "selected for" in the first place. This is a basic tenet of natural selection. A new trait must arise in order to advance or decrease the fitness of the individual, and hence, its ability to pass on its genes.</span>
Answer:
The correct answer here is D) None of the above
Explanation:
Lactose intolerance and sucrose intolerance in themselves are not practices but side effects of practices that affect health concerns.
For instance, research shows that cultures with a long history of dairy farming and milk drinking or at least a history of drinking milk have a much higher likelihood to be <u>lactose tolerant</u> than those who don't. And when they can tolerate lactose their bodies take note of this and records the same in their genetic databank.
Cheers!
Answer:
The correct option is C. receptor dimerizaton.
Explanation:
Growth Factors are protein substances found in our blood and play an important role in intercellular communication. These protein substances bind to receptors on the surface of the cell, with the main result of the activation of cell proliferation and / or differentiation. Many growth factors are very versatile, stimulating cell division in numerous different cell types, while others are specific to a particular cell type.
For the activation of a growth factor, dimerization or oligomerization of the receptor is necessary for kinase activity to occur, triggering intracellular signaling cascades. The dimerization can be between two identical receptors (homodimerization) or between different members of the same family (heterodimerization). The dimerization of the receptor, leads to the activation of its tyrosine kinase and the transphosphorylation of the tyrosine residues, releasing a signal transduction into the cell.
