The three-dimensional compositions have more silicon in comparison to those composed of independent tetrahedra.
The silicate minerals refer to the most general of Earth's minerals and involve feldspar, quartz, mica, pyroxene, amphibole, and olivine. On the other hand, the silica tetrahedra composed of oxygen and silicon, produce sheets, chains, and frameworks, and bonds with other cations to produce silicate minerals.
Answer: A. Extirpation
Explanation:
The term extirpation is also known as local extinction. It is situation whereby a particular species ceased to exist in an environment where it was once found, though it's existence is still observed elsewhere.
Extirpation maybe as a result of unfavorable environmental and human factors such as hunting, food scarcity and climate variation.
Answer:
The Thymus is a unique gland which protects the body against autoimmunity when the immune system act against itself.Hence the Thymus plays a significant role the dual systems i.e.,the lymphatic system (body’s defensive mechanism) and the endocrine system
Explanation:
The Thymus is special gland located anteriorly to the chest directly behind the sternum and in between the lungs. Active until puberty and gradually shrinks to become fat after puberty.
Function: Prior to birth and during childhood thymus engage in producing and maturation of T-lymphocytes or T-cells a particular type of white blood cells which defence the body against infectious disease germs.Though the organ does not function throughout the life span but it plays a significant role protecting the body against autoimmunity refers to an immune system works against itself .Therefore the thymus plays a key role in lymphatic system and an endocrine system.
Secretion:Thymus secretes Thymosin a hormone it instigates the development of T-Cells ( disease resisting cells) Thymosin stimulates the development of T-Cells until a human attains its puberty.
At the age of 75 thymus becomes a fatty tissue.
