Answer:
Some diseases are more common in certain groups of people, such as Caucasians or African Americans because individuals in such ethnic groups often share certain alleles (versions of their genes), that have been passed down to them from common ancestors and a particular genetic disorder may be more frequently seen in such groups if one of these shared genes contains a disease-causing mutation.
Explanation:
Some genetic diseases are frequently seen in certain ethnic groups like Caucasians or African Americans. Individuals in such groups often share certain alleles (versions of their genes), that have been passed down to them from common ancestors and one of these shared genes may contains a disease-causing mutation.
Examples of certain genetic disorders that are more common in particular ethnic groups include the Tay-Sachs disease, which is more common in people of eastern and central Europe (Ashkenazi), Jewish or French Canadian ancestry and the sickle cell disease, which occur among people of African, African American, or Mediterranean heritage.
Some genetic disorders are more common in people whose ancestry can be traced to a particular geographic area. The factors that can lead to development of populations with very different genetic allele frequencies include their geographic origin, selection, patterns of migration, historic events, etc. Certain natural barriers like oceans and other water bodies, high mountains, large deserts, or major cultural factors had prevented communication and interaction between people. So mating was restricted within the group, and this produces genetic marker differences and differences in the presence of specific disease-related alleles.
Answer:
d.The wing-assisted incline running theory postulates that wings were initially used to maintain balance while climbing up slopes.
Explanation:
Two theories were given to explain the origin of avian flight. The top-down theory suggested that the birds' ancestors were tree dwelling species. They took help of wings to glide from tree to tree in order to avoid predator or catch prey. The bottom up theory suggested that the birds' ancestors were ground dwelling species. They took help of wings to maintain a balance and provide a lift for efficient running.
Wing-assisted incline running was a mixture of both the above theories and gave a balanced view point. According to it, birds' ancestors used wings to maintain a balance while running up inclined slopes. The wings helped them to save energy while scaling slopes and eventually a flight mechanism was also developed.
The answer is B. CO2 + H2O + Sunlight ----> Glucose + O2
46 Cromosomas
Las células del ser humano tienen 23 pares de cromosomas, 22 pares de autosomas y un par de cromosomas sexuales. Por tanto, cada individuo tiene 46 cromosomas en sus células. Por lo tanto, el número de cromosomas presentes en una célula nerviosa de un ser humano es de 46 cromosomas.
<span>Many planets are made of gas, and in different situations, the atmosphere can be destroyed.
The sun which is burnt measures atmosphere and in the same case planets can be in a good situation on galactic map and a great condition in the atmosphere as well as earth.
For example, the mass of an object can attract a smaller object causing gravity. The bigger the masses of a planet when it is in the right condition the more atmosphere it can attract if there is any floating on the planet. If it is big it will make a gravitational influence and gather more gases.</span>
