Answer:
A DNA marker
Explanation:
also known as a size standard or a DNA ladder) is loaded into the first well of the gel. The fragments in the marker are of a known length so can be used to help approximate the size of the fragments in the samples.
<span>Worldwide, industry accounts for about 24 percent of all water use, but this is an average amount. Industrial water use can be as much as 70 percent in some highly industrialized European countries or as low as 5 percent in less industrialized countries, such as Bolivia. Most of industrial water is used as a cooling agent for power plants, but unlike agricultural water use, the majority of the water is non-consumptive. Industrial plants usually draw water out of a river or ocean, use it for cooling their equipment, and then return the water to its origins. If care is taken to avoid contamination, the water is not degraded or polluted, and it can be used again for other purpose</span>
Answer:
Vestigial structures do not have a function, yet they are homologous to functional structures in related species. They are important because they provide clues to the ancestry of the organism. Many species look similar as embryos.
The correct answer is option (B) lemon juice.
pH refers to the logarithmic scale used to indicate the acidity or basicity of an aqueous solution. It is the negative of the base 10 logarithm of the activity of the hydrogen ion. Solutions with a pH less that 7 are considered acidic and the solutions with a pH greater that 7 are considered to be basic. A pH of 7 is neither an acid nor a base and is considered neutral.
An acid has a high concentration of hydrogen ions (H+) and a base has a low concentration of hydrogen ions. Higher the hydrogen ion concentration, pH is acidic. Among the given substances, lemon juice has a pH of 2, urine has a pH of 6, tomato juice has a pH of 4 and black coffee has a pH of 5. Since lemon juice has a pH of 2, it has the lowest –OH ion concentration.
