Answer:
When you eat, food passes from the throat to the stomach through the esophagus. A ring of muscle fibers in the lower esophagus prevents swallowed food from moving back up. These muscle fibers are called the lower esophageal sphincter 
Explanation:
 
        
                    
             
        
        
        
Answer:
Haploid
Explanation:
Haploid describes a cell that contains a single set of chromosomes. The term haploid can also refer to the number of chromosomes in egg or sperm cells, which are also called gametes.
 
        
             
        
        
        
"More people walk to school or work" is the scenario among the choices given in the question that <span>would most likely lead to a higher level of physical fitness among people who live in a city. The correct option among all the options that are given in the question is the second option or option "B". I hope it helps you.</span>
        
             
        
        
        
The cell membrane has selective permeability and chooses which to pass through. Non polar molecules can pass easily with diffusion, but ions cannot.
        
                    
             
        
        
        
Answer:
D. 100%
Explanation:
In humans, males have only one copy of the X chromosome in their cells. Therefore, human males express all the X-linked genes present on their X chromosomes irrespective of the recessive or dominant nature of the allele. This occurs since males do not have one more copy of the X chromosome to carry another allele for the gene. So, all the X-linked alleles present on the X-chromosomes of the human males are expressed. 
For example, human males with genotype X^cY and X^hY express colorblindness and hemophilia respectively. Though, human females express these recessive X-linked disorders in homozygous genotype only.