Answer:
The basic difference between SEM and TEM is that TEM generates an image with the assistance of radiation that goes through the specimen, while the images generated by the SEM take place with the assistance of electrons getting released from the surface of the specimen.
SEM is primarily used to examine the composition of the surface, with the help of SEM one can study the microbes present in the ecological niche like in the lining of the gut and human skin. Due to its great depth, it is considered the electron microscope analog of a stereo light microscope. It helps in providing complete images of the cells present on the surface, which are not easy to get with the help of TEM. Due to its enhanced functionality, it can also be used for size determination and particle counting, and also for process control.
A portal of entry<span> is the site through which micro-organisms enter the susceptible host and cause disease/infection. Infectious agents enter the body through various </span>portals<span>, including the mucous membranes, the skin, the respiratory and the gastrointestinal tracts.</span>
Answer: B
Explanation:
Ammonia is so toxic that it can be transported and excreted only in large volumes of very dilute solution. As a result most terrestrial animals simply don't have access to sufficient water to routine excrete ammonia.
The main advantage of urea is its very low toxicity. Animals can transport urea in the circulatory system and store it safely in high concentrations. Also much less water is loss when a given quantity of nitrogen is excreted in a concentrated solution of urea than would be in a dilute solution of ammonia.
Answer: 4. Problem solver
Explanation: you're working to fix a known problem
Answer:
Explanation:
Actually it was the experimental results of other scientists. The main stems of the theory was the indivisibility of small spheres (his image) that represented the elements he knew which reacted with other elements.
They seemed to give the same ratios in reactions (definite proportions) and multiple whole number ratios. Look up Lavoisier.
