Answer:
Explanation:
"Nature does this job through a process called the water cycle. Also known as hydrologic cycle, the water cycle is a phenomenon where water moves through the three phases (gas, liquid and solid) over the four spheres (atmosphere, lithosphere, hydrosphere and biosphere) and completes a full cycle. The water cycle has many effects: it regulates the temperature of the surroundings. It changes weather and creates rain. It helps in conversion of rocks to soil. It circulates important minerals through the spheres. It also creates the many geographical features present on earth like the ice caps of mountains, icebergs, the rivers and the valleys, lakes, and more. Hence it is quite important to understand and learn the processes of the water cycle."
-Water cycle a guide for students.
Answer: half life
Explanation: Radioactive decay follows first order kinetics and the time required for the decay of a radioactive material is calculated as follows:
t= time required
k= disintegration constant
x= amount of substance left after time t
a= initial amount of substance
when one half of the sample is decayed, one half of the sample remains and t can be represented as 
at 
, 
Answer:
Option 2 and 4 are correct
Explanation:
The reactants in the attached image have more enthalpy and hence less stability as they are more reactive. Thus, Product is more stable than the reactants.
This is an addition reaction in which two reactants add up to form the product.
Very less activation energy is required as the reactants themselves are unstable, possess high energy and hence are very reactive.
Reactants have more energy than the products.
