Answer:
<em>Hox </em>Gene
Explanation:
First, you're question is very vital, there are many ways in classifying along with identifying all living organisms that includes; morphological analysis, molecular systematics (studying the similarities and differences of the genetic data such in the sequences of DNA, RNA, and rRNA ), homology, cladistics, etc. based on phylogenetic tree, which the study of the evolutionary among various species.
But through it said that all living organisms shared one common ancestor. However, what makes them different from one to another is the homeotic genes that called <em>Hox </em>Genes; which specify the fate of a particular segment or region of the body, meaning the number and arrangements of the<em> Hox</em> genes varies considerably among different types of animals.
For instance, Sponges have at least one homologous to<em> Hox</em> genes, also insects have nine or more <em>Hox </em>genes resulting in multiple <em>Hox </em>genes occur in a cluster in which the genes are close to each other along a chromosome. Therefore, increases in the number of<em> Hox</em> genes have been instrumental in the evolution of many animals species with greater complexity in body structure.
Overall, more <em>Hox</em> genes, more complexity in body structure resulting in the differences of their morphological structure.
Hope that answered your question!
Two scientists testing different hypotheses about the same question
<u>Answer:</u>
<em>The two major processes by which bacterial populations produce genetic diversity are gene transfer and mutation.</em>
<u>Explanation:</u>
Gene transfer in bacteria occurs through conjugation. In the process of conjugation, the plasmid gets transferred from bacteria to another. Mitosis leads to the formation of two identical individuals.
In this process, the chromosome and the DNA content of the daughter cell remains the same as the mother cell. Bacteria also divides by the process of binary fission.
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.
