The RNA world hypothesis states that the earlier life-forms had relied only on RNA (Ribonucleic Acid) for the purpose of catalyzing the chemical reactions, and storing the genetic information. This hypothesis was proposed by Leslie Orgel, Carl Woese, and Francis Crick.
This hypothesis states that long before the living forms evolved to use DNA as the genetic storage material, the RNA molecules served the purpose of both storing the genetic information and carrying out catalysis, but because of its instability, DNA evolved.
Hence, the answer is RNA world hypothesis.
A tympanic membrane, (is also called a tympanum), is the circular patch of skin directly behind the frog’s eye that we commonly call an eardrum. It functions much like our’s does.
The tympanum sends sound waves to the middle of the war then to inner ear, which allows a frog to hear both in the air and below water.
Answer: the cfu/g Gram-negative bacteria in the fecal sample is C = 3.0 × 10^3
Explanation:
We know that; Gram negative bacteria looks pale reddish in color under a light microscope from Gram staining.
therefore
There are 30 red bacterial colonies counted.
1 mL of from tube 1 was removed and added to tube with 99 mL saline (tube 2) dilution is 1/100.
transferred volume into the plate is 1 mL.
Now, we have to determine the cfu/g Gram-negative bacteria in the fecal sample
Formula to calculate CFU/g bacteria in fecal sample is expressed as;
C = n/(s×d )
where C is concentration (CFU/g)
, n is number of colonies
, s is volume transferred to plate
, d is dilution factor.
so we substitute
C = 30 / ((1/100) × 1)
C = 30 / 0.01
C = 3000
C = 3.0 × 10^3
THERFERE, the cfu/g Gram-negative bacteria in the fecal sample is C = 3.0 × 10^3
Explanation:
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