Answer: 
Water, carbon dioxide, and oxygen are among the few simple molecules that can cross the cell membrane by diffusion (or a type of diffusion known as osmosis ). Diffusion is one principle method of movement of substances within cells, as well as the method for essential small molecules to cross the cell membrane.
 
        
             
        
        
        
Answer:
Please find the explanation to this question below
Explanation:
The ATP cycle is the series of reactions involving glycolysis, Krebs cycle and oxidative phosphorylation that produces/synthesizes ATP in living cells. These processes collectively is called CELLULAR RESPIRATION. Glycolysis produces 2ATP molecules, Krebs cycle produces 2ATP while the electron transport chain (oxidative phosphorylation) produces 34ATP molecules. 
This cycle of ATP as explained above is an important frequent event in cells because all organisms need energy to carry out their metabolic activities. ATP is the energy-carrying molecule that stores and releases energy for use by the cells, hence, it needs to be produced on a frequent basis. 
ATP can be likened to a charged battery ready to release its stored energy. The energy is stored in the phosphate bonds that makes up its structure. When ATP releases its energy, it becomes ADP (Adenosine diphosphate). However, ADP is a reactant in the ATP cycle, which is phosphorylated with an inorganic phosphate (Pi) and catalyzes by ATP synthase to form ATP. 
 
        
             
        
        
        
Answer:
22:- in mitosis stem cells and somatic cells cell division occurs and in meoisis germ cells cell division occurs 
23:- at end of mitosis 2 daughter cells formed and meiosis 4 daughter cells formed 
24:- in mitosis cells are same and in meiosis cells are different 
l know only those questions answers 
 
        
             
        
        
        
Dust in the air because the water molecules need something to condense around.