Question

question 20 (1 point) cell shape, size, and special characteristics can be determined by gram staining. acid - fast staining. endospore staining. all of the above. question 21 (1 point) saved are molecules that stimulate a response by t and b cells. antibodies antigens interferons platelets question 22 (1 point) saved identify the method of macroscopic testing listed below. gram staining direct antigen biochemical testing animal inoculation

Explanation:

• Question 20: Gram - staining differentiates bacteria into Gram - positive and Gram - negative based on cell wall properties (which can relate to cell shape etc. in a general sense). Acid - fast staining is used for acid - fast bacteria (e.g., Mycobacterium) and can show cell characteristics. Endospore staining highlights endospores (a special characteristic of some bacteria). So all these staining methods can give information about cell - related features.
• Question 21: Antigens are foreign substances that can trigger an immune response involving T and B cells. Antibodies are produced by B cells in response to antigens. Interferons are signaling proteins in the immune system (not the stimulators of T and B cells in the way antigens are). Platelets are involved in blood clotting, not in stimulating T and B cells.
• Question 22: Animal inoculation is a macroscopic testing method where a pathogen is introduced into an animal (a whole - organism level, macroscopic approach). Gram - staining is a microscopic technique. Direct antigen testing can be at a molecular level (not macroscopic in the sense of whole - organism testing). Biochemical testing is usually at a cellular or molecular level (e.g., testing for enzyme activities etc., not macroscopic in the same way as animal inoculation).

Answer:

• Question 20: all of the above.
• Question 21: Antigens.
• Question 22: animal inoculation.