Answer:
Sexual reproduction produces genetic variation in offspring.
Explanation:
Ans.
Sickle-cell disorder is a genetic disorder, which shows defected red blood cells, due to mutation in the genes for hemoglobin protein.
Malaria is common in sub-Saharan Africa region and there, natural selection favored gene for sickle cells, because it might be beneficial to people having sickle cell disease that makes them able to survive in such condition and transmit their genes to offspring.
On the other hand, in those Africans, who moved to United States, where malaria is uncommon or absent, natural selection favored normal, wild type genes, resulting in fewer people with defected sickle cell.
Hence, sub-Saharan African population shows higher percentage of mutated gene for sickle cell as compared to population of United States.
Thus, the evolutionary process behind this difference is 'natural selection.'
Answer:
a move from the fundamental niche to the realized niche for both species.
Explanation:
The niche of an organism is the functional role of the organism in the community or the ecosystem as a whole. This include the environment an organism lives and all the jobs it does in it.
Fundamental niche refers to all the possible functional roles of an organism in an ecosystem while realized niche refers to the specific roles the organism is limited to as a result of resource limitation, competition or other factors.
Resource partitioning involves the division of limited resources among organisms so as to avoid competition within the niche.
<em>Hence, resource partitioning causes a move from the fundamental niche of an organism to the realized niche of that organism. </em>
Gases in Earth's Atmosphere. Nitrogen and Oxygen are by far the most common. Dry air is composed of about 78% Nitrogen (N2) and about 21% Oxygen (O2). Argon, Carbon Dioxide (CO2), and many other gases are also present in much lower amounts; each makes up less than 1% of the atmosphere's mixture of gases.
So therefore Oxygen is the gas that makes up the largest portion of the Earths Atmosphere.
