Answer:
The correct option is option b that is<em> Homo erectus</em> is the common ancestor of<em> Homo neanderthalensis</em> and<em> Homo sapiens.</em>
Explanation:
<em>Homo erectus </em>appears about 2 mya, possibly during the Pleistocene epoch and are considered as direct ancestor of human.They are called as upright man as they use legs for walking without any support.They are thought to be capable of doing certain things like hunting, starting fire,art making, create speech etc.
<em>Homo neanderthal</em> was the most recent ancestor species of modern human as they appear about 40,000 years ago.
They became extinct as they did't fight against environmental hazards and the major cause of their extinction that scientists have claimed that they did't adapt the modern techniques that the modern human does.
During T cell maturation, the t cells must pass two tests. first, immature t cells that can recognize MHC molecules are Selection. Second, immature t cells that recognize and bind to molecules normally found in the body are Activation.
Selection is the first test that T cells must pass. During this process, immature T cells that can recognize MHC molecules are selected. MHC molecules are found on the surface of cells and are involved in antigen presentation. When T cells come into contact with MHC molecules, they are able to recognize the molecules and begin the process of selection. During selection, the T cells that recognize MHC molecules are chosen over those that do not. This helps ensure that the cells that are selected are those that can properly respond to antigens.
The second test that T cells must pass is activation. During activation, T cells that recognize and bind to molecules normally found in the body are selected. These molecules are called self-antigens and can include proteins, carbohydrates, and lipids. When T cells come into contact with self-antigens, they are able to recognize the molecules and begin the process of activation. During activation, the T cells that recognize self-antigens are chosen over those that do not. This helps ensure that the cells that are selected are those that will not attack the body’s own cells.
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<h2>Simple contusion </h2>
Explanation:
Simple contusion in eye
- Simple contusion is also known as bruise or commonly known as black eye which is used to describe the discoloration that occurs around an eye after a trauma to the eye or surrounding tissues
- It is caused by broken blood vessels under the surface of the skin is typically accompanied by swelling
- A serious condition that can accompany a black eye is bleeding inside the eye, in the space between the back side of the cornea and the front of the iris which is called hyphema
Scleral hemorrhage
- Scleral hemorrhage also known as subconjunctival hemorrhage
- When small and delicate blood vessels break beneath the tissue covering the white of the eye (conjunctiva), resulting eye redness then this condition is known as subconjunctival hemorrhage
- A subconjunctival hemorrhage usually is benign, causing no vision problems or significant eye discomfort despite its conspicuous appearance
- But eye redness also can be a sign of other types of potentially serious eye conditions
<em>Protein synthesis is the process whereby biological cells generate new proteins and it is balanced by the loss of cellular proteins via degradation or export.</em>
It helps the body build muscles and protects from germs and virus.
In the lac operon, glucose also plays an important role along with lactose. When Lactose is present in the environment along with glucose then it cannot deactivate the regulator gene [repressor], as a result, the repressor will bind to the operator and the transcription will be blocked.
When Lactose is present in the environment without glucose then the Catabolite repressor protein will bind to the CAP Site, and lactose will bind to the repressor [regulatory gene product], as a result, the repressor gets deactivated and the transcription takes place.
Lac operon: It is a set of three structural genes z, y, and a which are all transcribed and regulated under one single promoter. The three genes code for β-galactosidase, lactose permease, and transacetylase respectively.
β-galactosidase is responsible for breaking the lactose into glucose and galactose, lactose permease is responsible for transporting lactose across the cell membrane and transacetylase attaches a particular chemical group to target molecules.
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