Answer:
The correct statement concerning the cell membrane lipid molecules is that "energy is not expended during diffusion" (Option d)
Explanation:
Biological membranes are formed by two lipidic layers arranged with their hydrophilic polar heads facing the exterior and the interior of the cells, and their hydrophobic tails against each other. Membranes are fluid, which means that molecules that form it have the capability to move through it.
Lipids can easily change places with other neighbor lipids by <u>lateral diffusion</u> in the same layer. This is passive diffusion, which means that it does not need energy to happen.
Lipids can also diffuse transversally to the other layer, but this kind of movement is not as easy as lateral diffusion.
There are also other lipidic movements as rotational diffusion that imply the rotation of the molecule.
Through this lipidic bilayer, there is also a passive transport of some particles from one side of the cell to the other which happens because of concentration differences.
With increase in altitude atm pressure decreases... :)
A sudden and violent movement of the ground sometimes causing great destruction as a result of movements within the earths crust or volcanic action.
<u>Answer:</u> The weight of the person above the surface of a planet is 635.83N.
<u>Explanation:</u>
To calculate the weight of a person, we use the formula:
....(1)
where,
w = weight of an object
m = mass of the person = 65kg
g = acceleration due to the gravity of the planet
For the calculation of weight, we need to first find the acceleration due to gravity and for that we use the formula:

where, g = acceleration due to gravity = 
G = Universal gravitational constant = 
M = mass of the planet = 
r = distance of the person from the planet = 
Putting values in above equation, we get:

Putting this value in equation 1, we get:

Hence, the weight of the person above the surface of a planet is 635.83N.