Answer:
Hi there!
Your answer is:
It is very important for the cell membrane to be <em>semi-permeable</em> because the ability to pick and choose what comes in and out of the cell keeps the cell safe! The membrane can choose to block out nasty germs and can also choose to get rid of internal waste.
An example of when this is important is in this scenario:
Let's say the cells are in a really salty solution. Naturally, salt will want to pull the water out of the cell. If the membrane <u>wasn't</u><u> </u> semi permeable, the water would listen to the salt and leave the cell. This would cause cell death. <u>BECAU</u><u>SE</u> the membrane is semi permeable, they can choose <em>not</em> to give the salt any water, keeping them alive
Hope this helps
The studies are designed this way b/c it removes the power of suggestion and the double-blind study keeps both researchers and participants in the dark. So this compared to who is receiving the treatment which is relevant b/c it stops the researchers from accidentally overbalancing the study participants, or unintentionally favoring their assessment of the conclusions.
The correct answer is B.
Genetic drift is one of the four evolutionary mechanisms. It changes the frequency by chance, aka at random.
For example. if you have 100 frogs in the population, 20 red, 20 green and 60 yellow, not all of the alleles are going to be passed down to the next generation because a portion of the population can be affected by a random event such as the flood. So, if the flood accidentally kills 20 red frogs, none of the offspring are going to be red by chance.
