Answer:
It is true that earth was once covered with oceans and little dry land.
Explanation:
Over the course of around four billion years, the Earth's oceans have lost about a quarter of their original mass. Today the atmosphere is rich in oxygen, which reacts with both hydrogen and deuterium to recreate water, which falls back to the Earth's surface. So the vast bulk of the water on Earth is held in a closed system that prevents the planet from gradually drying out. According to the researchers, the continents emerged relatively suddenly from an ocean that covered 95 percent of the Earth's surface. The appearance of large masses of dry land would have caused more extreme weather, changes in ocean currents and the emergence of proper seasons. In turn, these environmental changes may have led to rise in atmospheric oxygen that enabled the explosion of new life forms around 500 million years ago.
Answer:
The correct option is;
X, W, Y, Z
Explanation:
The parameters given are;
Spring (S), Spring Constant (N/m)
W, 24
X, 35
Y, 22
Z, 15
The equation for elastic potential energy, 
, is 
The above equation can also be written as 
Where:
k = The spring constant in (N/m)
x = The spring extension
Therefore, since the elastic potential energy, , of the spring is directly proportional to the spring constant, k, we have the springs with higher spring constant will have higher elastic potential energy, , therefore the correct order is as follows;
X > W > Y > Z
Explanation:
pH indicators are weak acids that exist as natural dyes and indicate the concentration of H+ (H3O+) ions in a solution via color change. A pH value is determined from the negative logarithm of this concentration and is used to indicate the acidic, basic, or neutral character of the substance you are testing.
