1. Supplementary angles : Two angles are supplementary if their sum is 180°.
For angle 1 and ∠COF to be supplementary,
∠1 + ∠COF =180°
must be satisfied.
We see in the figure that angle 1 and COF form a straight line.
The angle of a straight line is 180°.
∴ 1 is a supplement of ∠COF.
Answer : YES
2. Given : ∠COF =150° ;
AD is perpendicular to BF.
Here, ∠BOC + ∠COF = 180° , since they form a straight line.
∠BOC = 180° - ∠COF = 180° - 150° =30°
∴ ∠BOC = 30°
Answer : D. 30°
South American and Nazca tectonic plate boundary;
The boundary between the South American and the Nazca plates is a vibrant one. These two plates have the same density, so they collide and lift the land upwards, which is why the Andean Mountain Range formed. Occasionally there are earthquakes and they can be very strong. This is a convergent boundary.
Indian and Eurasian tectonic plate boundary;
The tectonic between the Indian and the Eurasian tectonic plates is also a convergent one, where we have two tectonic plates with the same density pushing against each other, and thus lifting up the land, which is how the Himalayan Mountain Range was formed. The earthquakes are relatively rare, and are of different velocity.
Pacific and North American tectonic boundary;
The border between these two plates is a a convergent one as well, but the Pacific plate has a smaller density than the North American one, so it is subducting underneath it. This brings in a very big geological activity, so there's multiple volcanoes and volcanic activities, as well as a big amount of earthquakes.
Ozone layer depletion was not noticed until 1979, while CFC’s have been around since 1920s because CFCs take time to enter the stratosphere and remain there for at least 60 years after their initial release.
Option: A
Explanation:
Ozone layer is found in stratosphere. Ozone plays a dual role in the environment. When it is in the ground surface zone it is a harmful gas but when its in the atmosphere it is a life saving layer which absorbs UV rays and protect human beings and animals from the harmful affect of poisonous gases.
Though ozone layer started depleting from 1920. But it came into notice from 1979 as CFCs take time to enter the stratosphere and remain there for at least 60 years after their initial release.
Britain controlled land in the U.S.
