Answer:
The studies of monozygotic or identical twins are used to analyze the degree of genetic influence versus the environmental contribution on a specific pathology, this is because monozygotic twins share 100% of their genes, meanwhile the dizygotic twins share only the 50% of their genes, approximately.
The studies conducted on twins are a special type of epidemiological study because this relation allows the researchers to evaluate and compare the influence of genetic and environmental variables.
Explanation:
Researchers have conducted twin’s studies to discuss the “nature and nurture” question, it is well known that genetics are associated with the environmental factors to produce the human individualities.
However, the twin studies are a perfect model to evaluate the shared genetic and environmental factors for the trait of interest; in addition, it can help to estimate the proportion of variance in a particular genetic variation versus the amount of influence of shared or unshared environment. It also can reduce the amount of genetic and/or environmental variability in a genetic study.
Sahu, M., & Prasuna, J. G. (2016). Twin studies: A unique epidemiological tool. Indian journal of community medicine: official publication of Indian Association of Preventive & Social Medicine, 41(3), 177.
The sodium hydroxide solution and vegetable oil underwent a chemical change.
<h3><u>Explanation:</u></h3>
The reaction between a base and a fat or fatty acid is called as saponification reaction. Here the base dissociates into the cation and hydroxyl ion. The hydrogen from the fatty acid of the oil reacts with the hydroxyl ion to form water which is basically the neutralization reaction. This cation now reacts with the rest of the fatty acid to form a bipolar molecule which is the soap. During the reaction, the solution becomes cloudy but with time, it again goes back to solution. The cloudyness appears because oil isn't soluble in water based solutions and the base is actually made solution in water.
Here the sodium hydroxide reacts with oil to form water and the soap molecule which is a chemical change.