Answer:
D. Carbon dioxide and water vapor
<span>Oxygen-15 is an isotope of oxygen, frequently used in positron emission tomography, or PET imaging. It has 8 protons, 7 neutrons, and 8 electrons. The total atomic mass is 15.0030654 amu.</span>
The corrrect option is D.
Since the scientist was trying to determine if substance A affect the rate of reaction of X and Y, the best thing to do is to make substance X and Y to react together first, he should then measure the time taken for the reaction to take place. Next, he should make X and Y to react together again, but this time in the presence of A. The time taken for the reaction to occur should be measures. The scientist can now compared the two time measurements and decide if there are difference between them or not.
A meteor for sure because that’s whats she exactly saw a meteor
Atherosclerosis refers to build up of plaques in blood vessels. This leads to obstruction of blood flow which results in mortality. The plaque development occurs at endothelial cells. This research by Dai, et al., 2004 aims to understand the functional and non functional physical features of endothelial cells in condition of specific blood flow pattern. They utilized 3D flow analysis to characterize flow patterns and used "athero-prone" and "athero-protective" waveforms. These were found to represent shear stress on carotid artery that could easily develop or resist formation of atherosclerotic lesion.
The analysis of results were done via cDNA microarrays for gene expression. The effect of waveforms was also checked through different parameters like expression and localization of junctional proteins, expression of adhesion molecules and expression of proinflammatory cytokines etc. The researchers conclude presence of phenotypic alteration depending upon shear stress in atherosclerosis sensitive and resistant human arterial geometries.
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