Evidence for evolution, in other words evidence of common descent, include fossils, which have shown a (fairly) steady change in morphology over time for some species. An example would be horse hooves: we have fossils that show when they were still three toed, then two toed, then one toe in our present day horses. Another piece of evidence is vestigial organs. An example of vestigial organs is wings in some flightless birds, such as the kiwi. Their ancestors used it in order to fly across the marine barrier into New Zealand, but natural selection and random genetic drift made them quickly lose the ability to fly. Nonetheless, they still have their wings, however small. It can be assumed that eventually, their wings would be reduced to small stubs fused to other nearby bones, as has been observed in their cousins.
Answer:
C. Gene trees are only useful studying the relationships of sequences from different species.
Explanation:
Gene tree traces the evolutionary history of a particular gene. It includes all the events like duplication and speciation. It helps to study the relationship of genes from different species. Often these are orthologous genes which came form the same ancestor and code for the same protein indifferent species. Gene tree also helps to study the relationship of genes in the same species. Often these are paralogous genes which evolved by duplication and code for similar but not identical proteins in the same species. Hence, the statement that gene trees are only useful for studying the relationships of sequences from different species is incorrect.
Answer:
Spectroscopy is the study of the interaction between matter and electromagnetic radiation as a function of the wavelength or frequency of the radiation. Simply, spectroscopy is the study of color as generalized from visible light to all bands of the electromagnetic spectrum; historically, spectroscopy originated as the study of the wavelength dependence of the absorption by the gas phase matter of visible light dispersed by a prism. Matter waves and acoustic waves can also be considered forms of radiative energy, recently gravitational waves have been associated with a spectral signature in the context of the Laser Interferometer Gravitational-Wave Observatory as well. Spectroscopy, primarily in the electromagnetic spectrum, is a fundamental exploratory tool in the fields of physics, chemistry, and astronomy, allowing the composition, physical structure and electronic structure of matter to be investigated at the atomic, molecular and macro scale, and over astronomical distances.
The spectrum is determined by measuring changes in the intensity or frequency of this energy. The types of radiative energy studied include: Electromagnetic radiation was the first source of energy used for spectroscopic studies. Techniques that employ electromagnetic radiation are typically classified by the wavelength region of the spectrum and include microwave, terahertz, infrared, near-infrared, ultraviolet-visible, x-ray, and gamma spectroscopy. Dynamic mechanical analysis can be employed to radiating energy, similar to acoustic waves, to solid materials. The types of spectroscopy also can be distinguished by the nature of the interaction between the energy and the material example:Absorption- when energy from the radiative source is absorbed by the material. Elastic scattering and reflection spectroscopy determine how incident radiation is reflected or scattered by a material. Crystallography employs the scattering of high energy radiation, to examine the arrangement of atoms in proteins and solid crystals. Coherent or resonance spectroscopy are techniques where the radiative energy couples two quantum states of the material in a coherent interaction that is sustained by a radiating field. Spectroscopic studies are designed so that the radiant energy interacts with specific types of matter.
Out of the following given choices;
mucosa
serosa
submucosa
muscularis externa
The answer is muscularis externa. This layer is one of the 4 layers (tunics) of the GI tract. It is found beneath the submucosa and is composed of smooth muscles. The smooth muscles are responsible for the involuntary movements called peristalsis, that move food along the gastrointestinal tract.
