Hydrogen bonding
(Between Adenosine and Thymine, and Guanosine and Cytosine)
Answer:
A) the pressure of Earth's crust upon Earth's mantle
Planet earth was probaly formed 30,thousand years ago the first life probably evolved 29 thousand years ago
B. Covalent (Bond) I hope this helps! ^^
The answer is: An air conditioner that turns on if the temperature gets too hot.
Even though they hurt you emotionally, Negative feedbacks serve their own important function. They keep your feet on the ground and prevent you from getting too arrogant.
This function is similar as a cooling air conditioner. Hot temperature in the comparison above represent your arrogance and the air conditioner represent the negative feedback.