Answer:
1) Skull and Vertebral column
2) Meninges
3) Cerebrospinal fluid.
Explanation:
Central Nervous system:
CNS is the abbreviation of Central Nervous system. CNS controls the whole body functions so it is the most important component of the body. CNS consist of two parts 1) Brain and 2) Spinal cord
Both of these organs are very important and hence need to be protected. Nature provided these organs with certain protective mechanisms these includes
1) Skull and Vertebral column:
Skull is present around brain and vertebral column is present around spinal cord. These structure provides mechanical support to soft parts of CNS.
2) Meninges:
These are the membranes that provide antiseptic environment to the brain and hence protect it from microbes and other harmful substances.
3) Cerebrospinal fluid:
This fluid is present inside meninges which nourishes the brain and protect it from mechanical stresses.
Answer:
Change in direction
Explanation:
"Rotation" refers to an object's spinning motion about its own axis. "Revolution" refers the object's orbital motion around another object.
Answer:
Which type of selection tends to increase genetic variation? A. Disruptive selection B. Directional selection C. Stabilizing selection
The Answer is option A (Disruptive selection)
Explanation:
Selection can either shift the mean value of a trait, reduce the trait's variation, or increase its variation.
Genetic variation which allows natural selection to increase or decrease frequency of alleles already in the population is a source of phenotypic variation as it refers to differences in all the hereditary information of members of the same species.
Disruptive Selection is important in maintaining variation and initiating speciation as it Increases Variation by favoring alleles corresponding to more extreme phenotypes. But for it to occur, the mean phenotype has to experience the lowest fitness. Disruptive selection affects the frequency distributions of alleles and genotypes within a population.
Disruptive selection is based on the variance of a trait in a population as it increases genetic variance by equalizing the frequencies of existing alleles at polymorphic loci (a genetic loci with two or more alleles). Disruptive selection maintains and may even increase variation in natural populations by favoring extreme phenotypes, individuals with extreme values for a trait have greater reproductive success than individuals with intermediate values.
Beacuse they died long time ago
When h forms a bond with h2o to form hydronium ion, h3o , this bond is called a coordinate covalent bond.
