<span>The ischemic penumbra can maintain metabolic demand with marginal blood flow from collateral circulation for a maximum of 50% before increasing in size. A penumbra is the area where the flow of blood at about 25 - 50% can maintain normal metabolic demands for 6 - 8 hours only. When it continues to increase, the human cells will die and other neurological activity will be suspended causing the person to die slowly.</span>
If two parents have dark hair, the child will most likely have dark hair.
If one has light and the other dark, the child has a 75% chance of having dark hair or a dark-dominated mix because the gene for dark hair is dominant.
If two parents have light hair, the child will most likely have light hair.
Of course, it gets a lot more complicated than this, the genes of the child's grandparents and great grandparents could be carried by the parents as well. So if the parents have dark hair but they each have a parent with light hair, the light hair gene will be carried by them and could be passed on to the child. That's how it is with genetic disorders, such as Systic Fibrosis or Sickle Cell Anemia.
Essentially, a control variable is what is kept the same throughout the experiment, and it is not of primary concern in the experimental outcome. Any change in a control variable in an experiment would invalidate the correlation of dependent variables (DV) to the independent variable (IV), thus skewing the results.
A single random allele from each pair of parent alleles will be passed on to the gamete.
Hey! they are usually single celled!
hope this helped xoxo