True please mrk as brailest answer
To prevent blood flowing back after each heartbeat. They ensure that the blood flows only in one direction (back to the heart).
Answer:
The greenhouse and enhanced greenhouse effects refer to the return of approximately <u>80</u> percent and greater than <u>80</u> percent of the heat radiated by Earth.
Explanation:
During natural greenhouse effect :
. Solar radiation reaches the earth
. Re-radiation of heat occurs
. Less re-emitted heat
. More heath escapes into space
Hence the greenhouse effect refers to return of 80% of heat radiated by Earth.
While during Human Enhanced Greenhouse effect :
. Solar radiation reaches earth
. Re-radiation of heat occurs
. More re-emitted heat
. Less heat escapes into space
Hence the enhanced greenhouse effect refers to return of more than 80% of heat radiated by Earth .
