True. Metamorphic rocks are pre-existing rocks that have been modified through the exposure to unusual temperatures and/or pressures. It has been used for blackboard, roofs, sidewalks, floors, and marble is an example of a metamorphic rock that is used to make floor tiles, countertops and it is carved into statues and was used extensively in the building of the Roman Colosseum and other historic buildings.
<u>Answer:</u>
The series dilution method is the step wise dilution technique where the dilution factors remain constant in each step.
The advantages of using the series of dilution method over simple dilution are stated below:
<em>a) Aids in reduction of a dense culture of cells to a more usable concentration.</em>
<em>b) In every step of dilution the specific amount of bacteria is removed. </em>
<em>c) Helps in the estimation of concentration of an unknown sample.</em>
<em>This sums up the advantage of using the series dilution technique.</em>
Answer:
time; point
Explanation:
The complete question is as follows:
The shortest length of time required to kill all test microbes at a specified temperature is the thermal death __________ whereas the lowest temperature required to kill all microbes in a sample within 10 minutes is the thermal death _________.
time; point
window; point
point; time
time; temperature
- When a population of bacteria gets killed due to exposure to high temperatures then this is termed as thermal death.
- The time taken to kill a specific microbe at a specific temperature is termed as the thermal death time. The length of the time taken depends on the nature of the target microbe and hence, varies from one to another.
- The lowest temperature that will kill all the microbes in a sample within ten minutes is defined as the thermal death point. The temperature at which the microbes get killed within 10 minutes also varies from one microbe to another.
- Thermal death results in the disruption of the cell membranes of the microbes and hence can kill the microbes.