Answer: osteoporosis
Explanation: Osteoporosis causes bones to become weak and brittle — so brittle that a fall or even mild stresses such as bending over or coughing can cause a fracture.
 
        
             
        
        
        
Active transport uses energy but diffusion and facilitated diffusion doesn’t that why they differ from each other 
hopefully that helps :)
        
                    
             
        
        
        
<span>Anton van Leeuwenhoek, </span>who designed and built the first microscope, also discovered microbes such as protozoa and bacteria from a drop of pond water. He also viewed bacteria taken from his teeth scrapings. He was also the first to discovered blood cells and human sperm cells.
        
                    
             
        
        
        
During the primary response  we display a latent period of no secretory antibody synthesis.
<h3>What is  latent period?</h3>
The term latent period refers to the time lag that exists between the time that an individual contacts a pathogen and when the person begins to have the capacity to infect others with the disease.
The latent period varies from one organism to another. For some organisms, the latency period is as long as six months or higher. During this period the infected person shows no sign of infection.
During this period, we display a primary response to the antigen of no secretory antibody synthesis.
Learn more about latent period:brainly.com/question/10696517
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Missing parts;
During which response to the antigen do we display a latent period of no secretory antibody synthesis? A. primary. B. secondary. C. tertiary. D. quaternary.
 
        
             
        
        
        
<span>Natural selection leads to the survival of the population with the most complex traits. your answer is d.</span>