Plants reduce the carbon dioxide (CO2) in the atmosphere and create more oxygen, which is needed by all organisms, through photosynthesis. :)
Well firstly, alleles are different versions of genes. A dominant allele will show it's trait regardless of if the organism only has one copy of the allele (heterozygous). A recessive allele will show the effect only if two copies of the allele are present (homozygous)
Simply put, the glass in the analogy traps the sun’s heat inside the greenhouse, warming the interior and not letting the heat escape, just like greenhouse gases (CO2, methane, etc) trap the sun’s heat in the atmosphere, warming the planet and preventing heat from escaping back into space.
All 3 of them explain the reason why people wear the mask to stop HIV