A buffer is a solution that maintains a pH of 7.

 

 

A. Intermediate host: The intermediate host harbors the larval or asexual stage of a parasite but does not support adult development or mating of helminths.

B. Secondary host: This term is sometimes used interchangeably with intermediate host, meaning it also supports only immature stages of the parasite rather than adulthood and reproduction.

C. Definitive host: The definitive host is where helminths reach maturity and undergo sexual reproduction. Adulthood and mating occur here.

D. Transport host: A transport (paratenic) host temporarily harbors the parasite without further development, serving mainly to pass it to another host.

E. Mating takes place in all hosts: Only the definitive host provides the environment for sexual reproduction and full maturity of helminths.

A. Staphylococcus: Staphylococcus species are Gram-positive cocci that possess thick peptidoglycan cell walls, giving them rigidity and shape. They do not naturally lack a cell wall.

B. Bacillus: Bacillus species are Gram-positive, rod-shaped bacteria with strong cell walls. They are also capable of forming endospores but are not wall-deficient.

C. Mycoplasma: Mycoplasma species naturally lack a cell wall, relying on sterols in their cell membrane for structural support. This absence makes them pleomorphic and resistant to antibiotics like penicillin that target cell wall synthesis.

D. Clostridium: Clostridium species are Gram-positive rods with thick cell walls and the ability to produce endospores. They do not naturally exist without a cell wall.