If the same base pairs are used to code for all organisms, why is there so much variation among organisms

The correct answer is due to the change in the sequence of codons of genes as a result of recombination.

Explanation:

Four types of nucleotide base pairs namely adenine, cytosine, guanine and thymine are present in the DNA sequence which controls the trait of an organism as they encode "proteins."

These base pairs are read by the ribosome during translation in the form of triplet known as codons. It is the sequence of these codons which directly controls the morphological and physiological trait of an organism.

These codons are present in the genes - a coding segment of DNA on chromosomes which during meiosis I undergo recombination via crossing over between homologous chromosomes which results in the change in the order of these codons thus changing the amino acid sequence and hence proteins. This is the basis of genetic diversity.

Thus, due to the change in the sequence of codons of genes as a result of recombination is the correct answer.

the correct answer is - d. china has a large and growing population.

the fact that china has a large (the biggest) population, and it is still growing, doesn't hinder the agriculture production in the country. in fact, it can for increased production in the agriculture, since there's more labor force, as well the sheer mass of people produces lots of scientists that come up with new inventions as to how to improve this sector. nice example is the inner mongolia region in china, in general dominated by the gobi desert, but few scientist came up with a nice idea as to how to make the region productive by using plants that are very resistant to droughts, so lots of people have been employed, and the region is becoming greener and greener each year, and the production of food in this region is also increasing.

hypoxemia refers to a below usual concentration of oxygen in the blood, mainly in the arteries. hypoxemia is an indication of an issue associated with circulation or breathing and may lead to various symptoms like shortness of breath.  

the condition is identified by determining the level of oxygen in the blood sample obtained from an artery. it can also be predicted by determining the oxygen saturation of the blood with the application of a pulse oximeter.  

the normal arterial oxygen is about 75 to 100 mm hg. the values underneath 60 mm hg is generally considered with the requirement for supplemental oxygen. the normal pulse oximeter readings generally range between 95 to 100 percent. the values under 90 percent are regarded as low.  

in the given case, the oxygen saturation is measured at 93 percent, hence, there is no need to administer oxygen, that is, one should withhold oxygen.