Answer:
A malaria outbreak causing allele frequencies to change is an example of <u><em>natural selection.</em></u>
Explanation:
Natural selection is a type of selection in which those organisms are favoured to live and reproduce which are better adapted to live in an environment. Due to natural selection, the allele frequencies of a population will tend to change with the passage of time. 
When the outbreak of malaria occurs, those organisms which do not catch malaria are able to survive and pass on their characteristics to their offsprings. the other organisms die and do not reproduce. This will cause changes in the allele frequencies.
 
        
             
        
        
        
T killer cell or Cytotoxic T cells  are the cells in animals that are used to destroy bacteria and viruses after combining with lysosomes.
<u>Explanation</u>:        
The T cells kills the bacteria and virus. The T cells can easily identify the pathogen when combined with the lysosomes. The activated T cells releases a material called perforin. This substance gets into the walls of the affected cell and punctures its walls. Due to hole in the walls, there happens discharge of fluid and electrolytes, which leads to the death of the cell.  The substance secreted is the cytolytic proteins from the lysosome which helps in destruction of the infected cells.  
 
        
             
        
        
        
Answer:
D) Some kind of exoskeleton, or hard outer covering 
Explanation:
Ecdysozoa is a clade of animals that gathers arthropods, nematodes and seven other phyla. These organisms have a type of exoskeleton, or hard outer lining that limits the growth of these animals. At some point in the life of these animals, the "exoskeleton" becomes tight and forces these animals to form a new exoskeleton in order to grow. The process of moving from one exoskeleton to another is called ecdysis and also happens in insects.
 
        
             
        
        
        
Cytomegalovirus infection is caused by infection by herpes
virus 5 or cytomegalovirus. The virus spreads easily via urine, saliva,
breastmilk, infected blood or organs, semen, cervical mucus or stool, and the
infected can shed the virus for months at a time. An infected mother can also
easily infect her child. Treatment for cytomegalovirus involves administration
of antiviral drugs such asvalganciclovir, ganciclovir, cidofovir, or foscarnet,
or a combination. For HIV cases, the condition is treated with Foscarnet, Cidofovir, Ganciclovir and
Valganciclovir.
 
        
             
        
        
        
No Because we a selectively breeding them the way we want so it is not evolutionary