Answer: The plasma membrane is called a selectively permeable membrane as it permits the movement of only certain molecules in and out of the cells. Not all molecules are free to diffuse. If plasma membrane ruptures or breaks down then molecules of some substances will freely move in and out of the cells.
Explanation:
In one day a scientist can travel = 80 km
In 10 days. a scientist can travel = 80* 10
= 800 km.
Answer:

Explanation:
Given that,
The position of a particle is given by :

Let us assume we need to find its velocity.
We know that,

So, the velocity of the particle is
.
Answer:
3.9 m/s
Explanation:
We are given that
Mass of car,m=
Initial velocity,u=0
Distance,s=5.9 m

Average friction force,f=
We have to find the speed of the car at the bottom of the driveway.
Net force,
Where 
Acceleration,


v=3.9 m/s
Answer:
A physical matter
Explanation:
A kind of matter with uniform physical properties