Answer:
D) D
Explanation:
In this phylogenetic tree only Eukaryotes contain membrane-bound organelles and the common ancestor Branch point is at D.
Trisomy 21 (nondisjunction) Down syndrome is usually caused by an error in cell division called "nondisjunction." Nondisjunction results in an embryo with three copies of chromosome 21 instead of the usual two. Prior to or at conception, a pair of 21st chromosomes in either the sperm or the egg fails to separate.
Answer:
Sex linked inheritance may be defined as the type of inheritance in which the trait or mutation is present on X chromosomes rather than on autosomes. Sex linked trait expression will depend upon the type of sex.
Two type of inheritance of sex linked trait are X linked dominant and X linked recessive trait. In X linked recessive trait, the male are more affected as they have only single X chromosome. Females should have both X chromosome affected for the expression of the trait. In sex linked dominant trait, a single X chromosome is enough for the expression of trait.
For example: Color blindness is an sex linked recessive trait, the mother generally passes the trait to their sons. Fragile X syndrome is a sex linked dominant trait in which the affected father will have all the affected daughter.
The correct answer to
this is:
“Microevolution”
Microevolution is an
evolutionary change that occurs to small group of species within a short span
of time. The cause of this occurrences are most commonly an external factor.
For the case of moth, t<span>he soot
produced by the Industrial Revolution in the 1800s resulted in trees to darken
and other places in England where moths liked to perch. Because of this, light
colored moths were more easily identified by predators against a dark
background. Dark colored moths had a larger survival advantage since they could
blend in against a similarly dark background. Natural selection or
microevolution favoured the darker moths, therefore their proportion within the
moth population increased.</span>