My theory is that . Mybe it changed because the flavor composition of the cracker changed or it dissolved in the saliva.
THEORY. :'3
-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.
Answer:
B. The membrane lets certain substances move across it freely, while others must move through a “gate”.
Explanation:
Selective permeability is a property of cellular membranes that only allows certain molecules to enter or exit the cell. This is important for the cell to maintain its internal order irrespective of the changes to the environment. For example, water, ions, glucose and carbon dioxide may need to be imported or exported from the cell depending on its metabolic activity. Similarly, signaling molecules may need to enter the cell and proteins may need to be released into the extracellular matrix. The presence of a selectively permeable membrane allows the cell to exercise control over the quantum, timing and rate of movement of these molecules.
Answer:
1. 1.00(1/2)^151/30.2= 31.3 g
2. 24g-->1.4 g = 4 half-lives, so 4*5730= 22920 years
3. 64g-->2.0g = 5 half-lives, so 12.5/5= 2.5 hours
