<u>Answer:</u>
<em>
heat is released by the combustion of 
of methane</em>
<u>Explanation:</u>
The value of enthalpy determines whether the reaction is exothermic or endothermic. If the enthalpy change is positive, then the reaction is endothermic (heat or energy released) and if the enthalpy change is negative then the reaction is exothermic (heat or energy absorbed).
![\Delta H \ reaction=[ 2(\Delta HfCO_2)+ 4(\Delta HfH_2O)]-[2(\Delta HfCH_4)+4(\Delta HfO_2)]](https://tex.z-dn.net/?f=%5CDelta%20H%20%5C%20reaction%3D%5B%202%28%5CDelta%20HfCO_2%29%2B%204%28%5CDelta%20HfH_2O%29%5D-%5B2%28%5CDelta%20HfCH_4%29%2B4%28%5CDelta%20HfO_2%29%5D)
=![2 ( -(393.5 KJ)/mol)-[2( -74.6 KJ/mol)+4(-241.82 KJ/mol)]](https://tex.z-dn.net/?f=2%20%28%20-%28393.5%20KJ%29%2Fmol%29-%5B2%28%20-74.6%20KJ%2Fmol%29%2B4%28-241.82%20KJ%2Fmol%29%5D)
![= -787 KJ/mol-[ -149.2 KJ/mol-967.28 KJ/mol]](https://tex.z-dn.net/?f=%3D%20-787%20KJ%2Fmol-%5B%20-149.2%20KJ%2Fmol-967.28%20KJ%2Fmol%5D)
<em>In this question, </em><em>the enthalpy of formation</em><em> has positive value and hence the </em><em>reaction is endothermic</em><em> in which the heat is released.
</em>
Sorry for a late answer... But here we go!
https://www.sciencelearn.org.nz/resources/102-methods-of-pollination
Altitude decreases the temperature in the troposphere....
Answer: Option A.
Polar ice cap in Antarctica.
Explanation:
Scientist drill ice cores from inside the polar ice cap in Antarctica to study variability of climate and differentiate that variability From global climate change. Each layer of the ice tells about weather and what the Earth was like when the first snow fell.
For example, Le grande says that as snow deposits into a growing glacier, the temperature of the air imprints on water molecules.
Icy layers hold particles,aerosols, sea salts, trace elements that were in the atmosphere before and they abide for thousands of years and provide evidence of past events.
