Answer:
It is difficult to cross.
Explanation:
The Sahara desert is a vast region about the size of the continental United States that is extremely dry and barren. The lack of water resources in the desert make the land unsuitable for agriculture and human population.
As a result, the Sahara acts as a giant natural wall both economically, culturally, and socially since relations between states to the north and south of the desert are difficult.
B shows the victoria lake.
Answer:
So the wavelength of light is 1015.7 nm
Explanation:
From Wein's displacement law, we can write the following formula;
here,
is the wavelength of maximum radiation in meters
T is the absolute temperature (in Kelvin) for maximum radiation
K is the constant has a value of 
Given here, T = 2853 K
And we need to find 
Putting the values in formula



the world's current population is 7.3 billion and the world population in 1915 was 1.8 billion. The increase over the past century is 7.3 billion - 1.8 billion = 5.5 billion. So, the correct answer would be "more than 5 billion" (option D).