Even though facilitated diffusion involves transport proteins, it is still passive transport because the solute is moving down the concentration gradient. ... A channel protein, a type of transport protein, acts like a pore in the membrane that lets water molecules or small ions through quickly.
        
             
        
        
        
The Cambrian explosion was a period at the Pre-Cambrian boundary of the geologic time scale at 542 Ma. At this boundary, the fossil record shows that animals suddenly appeared in a dramatic radiation of life. A radiation is the relatively rapid development of new types of organisms that derive from a common ancestor. The Cambrian explosion is important because it marks the origination of all major animal groups called phyla. 
        
             
        
        
        
Answer:
H. Immue and digestive
Explanation:
The immune system fights pathogens protects us from them, the digestive system destroys pathogens that may be in our stomach or intestines.
 
        
             
        
        
        
Answer:
475
Explanation:
The strand is only made up of Adenine, Thymine, Cytosine and Guanine. There will be the same number of Adenine as there are Thymine and the same number of Cytosine as there are Guanine.
We know there are 425 Thymine. This means there are also 425 Adenine. Therefore, you would subtract 850 (425x2) from 1800 to find the amount of Cytosine and Guanine left, which is 950.
Out of the 950, half will be Cytosine and half Guanine. 950/2 is 475.
 
        
             
        
        
        
Before carbohydrates are absorbed, the enzymes sucrase,
maltase and lactase digest disaccharides into monosaccharides in the small
intestine. Sucrase breaks down sucrose into glucose and fructose, maltase
breaks down maltose into two glucose, and lactase breaks down lactose into
glucose and galactose.