Answer: A
. the history of the Hoover Dam and its impact on the Southwest region.
Explanation:
This question is based on the article, ''The Hoover Dam'' by Michael Stahl. In it the author begins by describing what hydroelectricity is and how it came about.
The author then used the Hoover Dam to illustrate the points made about hydroelectricity by first giving a brief history of the construction of the dam and the sacrifices it took to build it. The impact the dam had on the area it supplies - the Southwest - was also analysed.
Answer:
The time it takes for light from stars to reach us is the distance to the star divided by this speed
Explanation:
light travels at 300,000 kilometers per second or 186,000 per second. The nearest star to us is the sun and it takes about 8.3 minutes for its light to reach us here on Earth
Answer:
See the explanation.
Explanation:
Gel electrophoresis is a technique used to separate DNA fragments by size and charge. Electrophoresis consists in applying a current through a gel that contains the molecules of interest. Based on their size and load, the molecules will travel through the gel in different directions or at different speeds, thereby separating each other. All DNA molecules have the same amount of charge per mass. Because of this, gel electrophoresis separates DNA fragments only by their size.
Electrophoresis allows us to see how many different DNA fragments are present in a sample and how large they are with respect to each other. We can also determine the absolute size of a DNA fragment by examining it next to a standard "scale" of fragments of known size.
Hope this helps!
Answer:
False.
Explanation:
- Ozone is a triatomic gas.
- Each molecule of ozone is made up of three atoms of oxygen.
- Ozone is an extremely important gas in the atmosphere as it absorbs the maximum of incoming solar radiation and the ultraviolet rays of the sun.
- But Ozone is an extremely reactive gas and is highly dangerous if inhaled for a longer time.
- It causes damage to the lung tissue and cause respiratory ailments.
- On the other hand ozone is one of the components of Photochemical smog.
- Inhaling a significant amount of this gas can cause death.
- Hence the given statement is False.
- The correct sentence is:
Ozone protects us when it is high up in the atmosphere, it is harmful to us when we are breathing it.
