Question

what are the major greenhouse gases contributing to global warming?
a. neon and argon found in rare air pockets
b. helium and hydrogen release into the air
c. carbon dioxide and methane emissions
d. oxygen and nitrogen absorbed by plants

what human activity primarily increases methane emissions?
a. urban development in coastal cities
b. expansion of industrial metal refining
c. logging and removal of natural habitats
d. agriculture and the raising of livestock

Explanation:

First Question:

To determine the major greenhouse gases, we analyze each option:

• Option a: Neon and argon are noble gases, not greenhouse gases.
• Option b: Helium and hydrogen are not major greenhouse gases.
• Option c: Carbon dioxide ($\ce{CO_2}$) and methane ($\ce{CH_4}$) are well - known major greenhouse gases that trap heat in the atmosphere and contribute to global warming.
• Option d: Oxygen and nitrogen are the main components of air and are not greenhouse gases.

To find the human activity that primarily increases methane emissions, we analyze each option:

• Option a: Urban development in coastal cities is more related to issues like habitat destruction and coastal erosion, not methane emissions.
• Option b: Industrial metal refining is more associated with emissions of heavy metals and other pollutants, not methane.
• Option c: Logging and removal of natural habitats mainly contribute to carbon dioxide emissions due to reduced carbon sequestration, not methane.
• Option d: In agriculture, especially livestock farming (e.g., cows produce methane during digestion), and also from rice paddies, agriculture and raising livestock are major sources of methane emissions.

Answer:

c. Carbon dioxide and methane emissions

Second Question: