The right answer is a. structures smaller than cells.
In the transmission electron microscope, electrons are emitted by heating a tungsten filament (or crystal of lanthanum hexaboride). These electrons are then accelerated with a voltage of between 200 and 1000 kV (1000 kV for the most expensive). Once the vacuum is in the cell, the electron beam is passed through a sample about 3 mm in diameter and less than 20 nanometers thick. Then this beam is focused with the help of magnetic lenses towards the screen or the photographic plate.
The operation of M.E.T is analogous to that of an optical microscope.
In light microscopy, a beam of photons is sent through a sample. This beam is then focused through optical lenses to the image plane of the lens. An enlarged image of the sample is observed.
Sexual reproduction occurs in the flower of flowering plants. Male gametes are produced in anthers of the flower and are found in pollen. Female gametes are produced in the flower’s ovary and are found in ovules.
Wake is the brief glow behind the meteor head. The wake is caused mainly by the green light of neutral oxygen atoms. Wakes last 1-10 seconds. Sometimes the term wake is also used to describe the area directly behind the meteor head.
The lids of the Petri dishes were inadvertently left on while being sterilized
Explanation:
The process of eliminating any microbe from a particular object to achieve a sterile aseptic environment is termed as sterilization.
Sterilization mainly aims to either remove, kill or make any microbe inactive by using various means such as irradiation, heat, pressure, etc.
In the given question radiation is used to sterilize the Petri dishes and thus, if sterilization is successful there should not be any contamination.
However, since there is contamination present amongst the bacterial colonies growing on agar plated in the Petri dishes this shows that the sterilization has not been done successfully and a possible reason for this could be that while sterilizing the<em> lids of the Petri dishes were kept on. </em>
