Question

regarding louis pasteurs experiments with the s - necked flask, which of the following statements is true?
air exchange was involved
a food source was provided
the possibility of contamination was removed
all preexisting microorganisms were killed
all choices are true
question 16 (1 point)
what type of stain distinguishes bacteria based on cell wall differences?
gram stain
negative stain
simple stain
flagella stain

Explanation:

1. In Pasteur's S - necked flask experiments: Air could enter the flask through the S - shaped neck, a broth (food source) was placed inside, by boiling the broth all preexisting microorganisms were killed, and the S - shape of the neck removed the possibility of contamination from the air.
2. Gram - staining is a method that differentiates bacteria based on differences in their cell - wall composition. Gram - positive bacteria and gram - negative bacteria have different cell - wall structures that cause them to stain differently with the Gram - stain.

Answer:

Question 15: All choices are true
Question 16: Gram Stain