A spiral galaxy is a galaxy where the stars and gas clouds are concentrated mainly in one or more spiral arms. Most spiral galaxies consist of a flat, rotating disk containing stars, gas and dust, and a concentration of stars known as "the bulge". The disk of stars orbiting the bulge separates into arms that circle the galaxy. These spiral arms contain gas and dust and younger stars that shine brightly before they dull. Most of the galaxies that scientists have discovered so far are spiral galaxies. One example of a galaxy in our solar system is The Milky Way. Spiral galaxies make up roughly 72 percent of the galaxies that scientists have observed. How the spiral arms form continues to puzzle scientists. One theory suggests the galaxy arms could be the result of density waves traveling through the outer disk. Galaxies at a whole are quite a fascination.
Aneuploidy can result in the final daughter cell if the spindle fibers fail to pull a chromosome toward the pole as in case of non-disjunction.
Explanation:
Aneuploidy is a condition which arises when one or more chromosome is missing in the final daughter cells.
Non-disjunction refers to the failure of chromosomal or chromatid segregation or separation during cell division. This results in erroneous meiosis or mitosis leading to the formation of final daughter cells or gametes with an extra or missing chromosome. This condition is aneuploidy.
Failure of separation or segregation of:
- Homologous chromosomes occur in Anaphase I, affects four daughter cells.
- Sister chromatids during Anaphase II, affects two daughter cells
This failure of separation leads to aneuploidy chromosomal abnormalities like monosomy, trisomy, etc which can cause diseases like Down’s syndrome, Turner’s syndrome etc.
Answer:
It is necessary.
Explanation:
If a member of a species doesn't reproduce, other members of the same species will become extinct.
It should be 50% and 25%.
