Answer: 43 x 10^6 CFU.
Explanation:
Plate count is a method used to determine the number of viable microorganisms in a sample. When the bacterial concentration is high, serial dilutions are carried out in a 1:10 sequence. <u>Then, the dilutions are successive dilutions keeping the dilution factor constant at each step</u>. Small aliquots of these dilutions are seeded in medium contained in a Petri dish where the bacteria grow forming colonies. Then the plates are incubated and colonies develop both within the agar and on the surface.
If the concentration of the seeded aliquot is too high, the bacteria will grow too much and it will not be possible to distinguish the colonies. <u>However, if the concentration is very low, the number of colony forming units (CFU) may be very low and thus can be counted</u>.
Colony forming units are calculated:
CFU = Number of colonies / (volume seeded on the plate * dilution).
The dilution is 10^-6, the number of colonies counted is 43, and usually the volume plated is 0.1 mL, so we replace that in the equation:
CFU= 43 / (0.1 mL * 10^-6)
CFU= 43000000 = 43 x 10^6
Nome popular: abobora
familia: cucurbitaceae
divisao: angiospermae
origem: america
ciclo de vida: anual
Answer:
millipedes were the first of these animal groups to evolve.
Explanation:
Fossils are structural remains of animals from the past. As these animals die, it takes years for the remains to be buried.
The millipedes are at the lower layer of the rock, next to insects, amphibians, and then rodents. This shows that millipedes existed and evolved before the rest of the found animal fossils.
