D. this is because when someone shows you a model of a cell, it is a diagram (typically) showing you the composition of it so that you can get a better idea of what the cell is and what the cell does.
There are three main reasons why people are concerned that cell phones (also known as “mobile” or “wireless” telephones) might have the potential to cause certain types of cancer or other health problems:
Cell phones emit radiofrequency energy (radio waves), a form of non-ionizing radiation, from their antennas. Tissues nearest to the antenna can absorb this energy.
The number of cell phone users has increased rapidly. As of December 2014, there were more than 327.5 million cell phone subscribers in the United States, according to the Cellular Telecommunications and Internet Association. This is a nearly threefold increase from the 110 million users in 2000. Globally, the number of subscriptions is estimated by the International Telecommunications Union to be 5 billion.
Over time, the number of cell phone calls per day, the length of each call, and the amount of time people use cell phones have increased. However, improvements in cell phone technology have resulted in devices that have lower power outputs than earlier models.
Answer:
Correct answer is 4. Under 2.5 people per sq. mi. (VERY low density)
Explanation:
Option four is the correct because areas such as Sahara have a low density and are not populated. The conditions of living are not allowing people in these type of areas to create some larger permanent settlements. The similar case is for example in Australia where 3/4 is covered with desert, which is practically uninhabited. Or we can also created a parallel with Greenland which also has a low density due to climate factor.
We can use rivers to get fresh water
71% of the Earth is covered in water.
