Answer:
The oil produced in United States is light and low sulfur content and they do not have proper processing facilities, hence purchase it from other countries.
Explanation:
About 9.93 million barrels per day U.S purchase oil from 86 countries. Because the crude oil present is not homogeneous in nature. It is very light in nature with low sulfur content or may be high,this particular factor depends upon the method of the refining. Most of the oil are being exported by the Saudi Arabia and then comes Russia followed by Iraq. Despite the collapse in price, U.S. dependence on foreign oil should continue to decrease.
Answer:
What is the function of DNA and RNA
Answer:
During transcription, only one strand of DNA is usually copied. This is called the template strand, and the RNA molecules produced are single-stranded messenger RNAs (mRNAs). The DNA strand that would correspond to the mRNA is called the coding or sense strand
Explanation:
The right answer is 34.78%
The interphase is the period of the cell cycle that the cell transcribes its genes and the chromosomes are duplicated. It can be subdivided into several phases:
* phase G1
* phase S: during which the chromosomal material is doubled by DNA replication. This is called chromosome duplication.
* phase G2.
Phase G1 is the longest phase of the interphase (its duration depends on the type of cell), followed by phase S, then phase G2.
To calculate the proportion of phase S in the interphase simply make the division:
phase duration S / interphase duration = 8/23 = 0.3478 (in percentage that is 34.78% (0.3478*100)).
Answer:
The animals present body structure is due to evolution. It is seen in each part including the structure of the heart. The vertebrate heart becomes complex from a simpler form.
Invertebrates, the heart of fishes is two-chambered having one auricle and one ventricle. The deoxygenated blood gets purified in the gills. They are aquatic and no lungs for breathing. The hearts pump a mixture of oxygenated and deoxygenated blood to the body.
The amphibians and reptiles have 3 chambered heart as they lead terrestrial mode of life. The gills modified into the lungs. The left auricle receives pure blood and the right auricle receives deoxygenated blood. The blood purified in the lungs and in the ventricle, both types of blood get a mix. The ventricle pumps the mixed-blood throughout the body.
In the case of birds and mammal, the heart is 4 chambered and the oxygenated and deoxygenated blood are separated. These two are higher vertebrates. No mix of pure and impure blood, the body receives only the oxygenated blood.
This shows to construct the phylogenetic tree of vertebrates - the fishes should be in the bottom, and above it amphibians, reptiles, then, mammals and birds on the top branch of the tree. As the chambers and structure of the hearts modified one after another.
