The correct answer is:
The principal cause of aneuploidy is chromosome nondisjunction during mitosis or meiosis. Polyploidy in nature can result either from the duplication of euploid chromosome sets from a single species or from the combining of chromosome sets from different species.
Aneuploidy is a phenomenon when there is the presence of an abnormal number of chromosomes in a cell (an extra or missing chromosome). Usually it appears as a result of improper cell division (chromosomes don’t separate) and it can cause many genetic disorders.
Polyploidy refers to a state when there are more than two sets of chromosomes (one from mother one from father). Triploid (three sets of chromosomes) and tetraploid (four sets of chromosomes) chromosomes are examples of polyploidy. This phenomenon is most common in plants.
Answer:
Valence electrons, or the electrons that are farthest from the nucleus.
The hormone calcitonin, which is produced by the parafollicular or C cells of the thyroid, has the opposite effect on blood calcium levels as does PTH. I hope this helps! : )
Answer:
Cochlear duct.
Explanation:
The mammalian ear is divided into three parts- outer ear, middle ear and inner ear. Ear is an important organ of the body responsible for maintaining the body's equilibrium.
The cochlear duct is well known as scala media. The cochlear duct is present between the perilymphatic chambers. This duct is interconnected at tip of the cochlear spiral.
Thus, the answer is cochlear duct.