Answer:
chemical reactions change reactant and produce new substance called products.
Explanation:
chemical reaction is a change which will produce a new substance. ( while physical reaction does not produce a new substance.
Answer:
Obtain specimen before antibiotics are given.
Explanation:
Antibiotics may be defined as the chemicals given to kill or restrict the growth of the bacterial infection. The antibiotics are not available for virus as they can change their DNA.
The sensitivity results can be accurate if the nurse is able to ensure the successful culture of the antibiotics. Throat culture specimen is taken from the pharyngeal area. The aseptic technique can be used by the nurse for obtaining the blood and urine specimen.
Thus, the answer is obtain specimen before antibiotics are given.
Kingdom, phylum, class, order, family, genus, and species is the classification chart levels in order from most broad to least.
Answer: The correct answer is -
D. Eukarya has similar evolutionary traits to archaea.
A phylogenetic tree (also known as evolutionary tree) is a diagrammatic representation (in the form of branch diagram) showing the evolutionary relationships among various organisms. It is constructed on the basis of similarities or differences in the genetic or physical characteristics of various species.
In the given phylogenetic tree, archaea domain shows more similarities to the domain eukarya as it has descended after the domain bacteria.
Thus, option D) is the right answer.
Answer:
Transmission electron microscope (MET): allows sample observation in ultra-thin sections. A TEM directs the electron beam towards the object to be increased. A part of the electrons bounce or are absorbed by the object and others pass through it forming an enlarged image of the specimen. To use a TEM, the sample must be cut into thin layers, not larger than a couple thousand thousands of angstroms. A photographic plate or a fluorescent screen is placed behind the object to record the enlarged image. Transmission electron microscopes can increase an object up to a million times.
A scanning electron microscope creates an enlarged image of the surface of an object. It is not necessary to cut the object into layers to observe it with an SEM, but it can be placed in the microscope with very few preparations. The SEM scans the image surface point by point, unlike the TEM, which examines a large part of the sample each time. Its operation is based on traversing the sample with a very concentrated beam of electrons, similar to the scanning of an electron beam on a television screen. The electrons in the beam can disperse from the sample or cause secondary electrons to appear. Lost and secondary electrons are collected and counted by an electronic device located on the sides of the specimen. Each point read from the sample corresponds to a pixel on a television monitor. The higher the number of electrons counted by the device, the greater the brightness of the pixel on the screen. As the electron beam sweeps the sample, the entire image of it is presented on the monitor. Scanning electron microscopes can enlarge objects 200,000 times or more. This type of microscope is very useful because, unlike TEM or optical microscopes, it produces realistic three-dimensional images of the object's surface.
