I’m not sure but I’m guessing the answer would be the first one !
        
                    
             
        
        
        
Answer: a. Increasing the surface area for diffusion 
Explanation:
When the air is inhaled through the nostrils, the air containing the oxygen the air diffuses inside the alveoli. The alveoli are the tiny sacs where air enters and exchange of gases takes place. From the alveoli the oxygen enters into the blood stream. The oxygen is utilized by the cells for respiration. The increase in network and number of the alveoli will increase the surface area for the diffusion of oxygen and hence, will speed up the respiration process. 
 
        
             
        
        
        
Answer:
I'm not too sure specifically for 9th grade. Though I am in 12th grade right now and currently using the Edrolo biology textbook which is solely based on the key dot points/skills for the entire subject. They also include past exam questions or similar exam style questions both multiple choice and short answer for each topic and chapter within the book.
Explanation:
 
        
             
        
        
        
The stem cell will go through mitosis to cause the differentiated cells it produces to also be cancerous; option A
<h3>What is mitosis?</h3>
Mitosis is a process in cells which accounts for the production of new cells by the division of cells.
Cancer results when there is abnormal growth and division of cells.
Therefore, mitosis occurs or stem cells to become cancerous.
Learn more about mitosis at: brainly.com/question/19058180
#SPJ1
 
        
             
        
        
        
Answer:
if its a couple with a trans man (female to male) they can have a baby if they havent had surgery.
a trans woman (male to female) can also have a biological baby with a woman if they havent had surgery.
They could also have had a baby in a past relationship though it wont be biological to the other parent.