Answer:
9/16
Explanation:
This is a typical dihybrid cross involving two genes; one coding for anridia (form of blindness) and the other for Migraine headache, both in humans. The allele for possessing anridia (A) is dominant over the allele for not possessing it (a) in the first gene, while the allele for having Migraine headache (M) is dominant over the allele for not having it (m) in the second gene.
A cross between a man that is heterozygous for both genes (AaMm) and a woman also heterozygous for the two genes (AaMm), this means that both parents are dominant for the two traits i.e. they both possess anridia and migraine headache.
Both parent cells will undergo meiosis to produce four possible combination of gametes in which the alleles are independent of one another in the gametes, according to Mendel's law of independent assortment. The gametes are: AM, Am, aM, am
These gametes are crossed using a punnet square (see attached image) to produce 16 possible offsprings in a phenotypic ratio of 9:3:3:1.
9- Offsprings with both anridia and migraine
3- Offsprings with only anridia but without migraine
3- Offsprings with only migraine but without anridia
1- Offsprings without both anridia and migraine
According to the question, the chance of an offspring expressing both traits i.e. having both anridia and migraine headache is 9/16
Answer:
c. Sarcomere
Explanation:
Sarcomere is one of the basic components of striated muscle that allows muscle contraction. That is, it is the contractile unit in the muscle cell.
The sarcomere is made up of a protein complex, the most important of which are actin and myosin. In the presence of Ca2 +, the ends of the myosin bind to nearby actin molecules and fold with great velocity. The actin filament then moves to the center of the sarcomere, triggering the approach of the two Z lines. This causes the sarcomere to shrink and, to a large extent, lead to contraction of the entire muscle.
Answer
A fish ladder can help fish migrate past barriers both natural and artificial (dams)
Explanation
A fish ladder is a structure constructed around natural barrier or artificial ones (dams and waterfalls) to facilitate fish migration in a natural manner. It is also called a fish way, fish pass or a fish step. With the help of such structures, fish protection and restoration is achieved thus boosting their numbers and maintaining a natural habitat.