IB ESS HL 6.1.4 Greenhouse Effect Questions

the principal greenhouse gases are carbon dioxide/ $\mathrm{CO}_{2}$, methane/ $\mathrm{CH}_{4}$, water vapour, nitrous oxide/ $\mathrm{N}_{2} \mathrm{O}$;
(no credit for anthropogenic GHGs, like tropospheric ozone, CFCs, HFCs)
b. ...and are found in the troposphere;
c. sun light (visible/short wavelengths) pass through GHGs/reach the Earth and warm its surface;
d. fwarm Earth surface is re-radiating energy outward as infra-red radiation/heat;
(no credit for "reflection" of light/heat)
e. GHGs are opaque to/absorb outgoing IR/long wavelength radiation;
f. much of the heat energy is therefore retained/raising the average temperature of the Earth surface (to $15^{\circ} \mathrm{C}$ );