The Cretaceous–Paleogene (K–Pg) extinction event (also known as the Cretaceous–Tertiary (K–T) extinction) was a sudden mass extinction of three-quarters of the plant and animal species on Earth, approximately 66 million years ago.
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Answer:
Option-B
Explanation:
The brain is an organ composed of neurons which controls all the voluntary and involuntary of animals. In humans, the brain is located in the skull where the brain is suspended in a fluid called cerebrospinal fluid.
As humans ages and becomes old aged, the neurons in the brain losing their ability to perform their function, if they are lost they cannot be regenerated.
The lesions appear on the white matter of the brain and the brain shrink. Due to these known and other unknown features, the process controlled by these neurons become inadequate and shows slower brain processing and weak memory.
Thus, Option-B is the correct answer.
Answer:
However, plants are also able to reproduce asexually
Explanation:
The two main components of the extracellular matrix are Elastin and Collagen.
The extracellular matrix is an intricate macromolecular network that is found in the extracellular space. The matrix is composed of polysaccharides and very diverse proteins, locally secreted and assembled forming a complex network that surrounds the cells. The matrix is highly developed in connective tissue and its derivatives. The extracellular matrix is formed mainly by proteins, glycosaminoglycans,proteoglycans and glycoproteins, organized in diverse networks that constitute the different tissues. <em>The most abundant proteins are collagen and elastin.</em>
Collagen is a family of very abundant proteins in the body of animals. Collagen molecules can represent 25 to 30 % of all body proteins. Its main mission in the tissues is to form a framework that supports the tissues and that resists the forces of mechanical tension.
The elastin molecules are very close to each other through links between the regions rich in the amino acid lysine. It is an abundant protein in may extracellular matrices and appears as a component of the so called elastic fibers, which are onsoluble aggregates of proteins.
