Cell membrane or in planet cells: cell wall AND membrane
-10grade/week
Explanation:
Given parameters:
Initial grade = 95grade
Final grade = 65grade
Time = 3weeks
Unknown parameter:
Rate of change of grade = ?
Solution:
Rate is defined as the change of a quantity with time.
Rate of change of grade = 
Rate of change of grade =
= 
Rate of change of grade = -10grade/week
The rate of change of the student's grade is -10grade/week. It implies that the grade of the student reduces by 10unit per week.
Agonist/antagonist
Agonist are drugs that bind and activate a receptor with effecting the response.If the effect results in maximum response it is considered as full agonist. However if the drug that binds to the receptor results only into partial efficacy in relation to the full activation of the receptor, this is considered as partial agonist.
Antagonist are drugs that blocks a biologic response of a hormone or another drug. They usually have affinity to the receptors but has no efficacy. This drug will just inhibit the activation of the receptors by the aganist.
We use Chargaff's rule to get the answer.
[A] + [G] = [C]+ [T].
[A] + [G] + [C] + [T] = 100%
Where is A is Adenine, G is Gaunine, T is Thymine and C is Cytosine.
In DNA, Adenine always pairs with Thymine, and Guanine always pairs with Cytosine.
Therefore if Thymine is 35%, then Adenine will also be 35% to make 70% in total.
The remaining percentage will be 100% - 70% = 30%.
The 30% will be shared equally among Cytosine and Guanine, at 15% each. Therefore Cytosine will be 15%