1. One reason is extinctions happen because of some kind of change in the environment where a life form lives. While some species can adapt to the changes, others die, and if enough die, the species becomes extinct. These are some of the biggest factors in the extinctions of particular species. 2. Contaminants in the environment, such as pesticides.
Answer and explanation:
The meninges
There are actually 3 parts—dura mater, arachnoid, and pia mater.
The brain is soft and mushy, and without structural support it would not be able to maintain its normal shape. In fact, a brain taken out of the head and not properly suspended (e.g., in saline solution) can tear simply due to the effects of gravity. While the bone of the skull and spine provide most of the safeguarding and structural support for the central nervous system (CNS), alone it isn't quite enough to fully protect the CNS. The meninges help to anchor the CNS in place to keep, for example, the brain from moving around within the skull. They also contain cerebrospinal fluid (CSF), which acts as a cushion for the brain and provides a solution in which the brain is suspended, allowing it to preserve its shape.
The outermost layer of the meninges is the dura mater, which literally means "hard mother." The dura is thick and tough; one side of it attaches to the skull and the other adheres to the next meningeal layer, the arachnoid mater. The dura provides the brain and spinal cord with an extra protective layer, helps to keep the CNS from being jostled around by fastening it to the skull or vertebral column, and supplies a complex system of veinous drainage through which blood can leave the brain.
The arachnoid gets its name because it has the consistency and appearance of a spider web. It is much less substantial than the dura, and stretches like a cobweb between the dura and pia mater. By connecting the pia to the dura, the arachnoid helps to keep the brain in place in the skull. Between the arachnoid and the pia there is also an area known as the subarachnoid space, which is filled with CSF. The arachnoid serves as an additional barrier to isolate the CNS from the rest of the body, acting in a manner similar to the blood-brain barrier by keeping fluids, toxins, etc. out of the brain.
Answer:
B) missense mutation
Explanation:
A type of base substitution that results in the replacement of one amino acid by another is called missense mutation. Missense mutations affect the mutated proteins in several ways. It may alter the amino acid composition of the active site of enzymes and render the enzymes inactive.
The wild type polypeptide chain has the following sequence of amino acids: Met-Ala-Gln-Arg-Glu-Leu. The mutated polypeptide has glycine in place of arginine. The rest of the amino acids are the same in wild type and mutated protein. This means that the mutation changed the genetic code of arginine into the genetic code of glycine resulting in the incorporation of glycine in position 4. This is an example of a missense mutation.
It must be able to store water for long periods of time
Answer:
D: nucleic acids - nucleotides
Explanation:
The correct monomer for carbohydrates would be monosaccharides
protein - amino acids
and lipid - fatty acids
