Question

select the correct answer from each drop - down menu
which transitions show the correct relationships?
global warming and its causes
global warming is a result of an increase in greenhouse gases. greenhouse gases are released into the atmosphere

deforestation and combustion of fossil fuels
deforestation is a major contributor to global warming. forests help to maintain the levels of oxygen in the air that make it possible for us
to survive
, there has been a surge in the levels of carbon dioxide in the air
the depletion of vast stretches
of forests
, other factors, such as the release of cfcs from refrigerators and pollutants from industries into the atmosphere, are
also respon
global warming
options in drop - down (partially shown): ordinarily, while, similarly, since
buttons: reset, next

Explanation:

1. First dropdown (after "Greenhouse gases are released into the atmosphere"): The context lists two sources of greenhouse gases, so "through" (implied logical preposition, but from the visible options, we infer the correct connecting logic: the phrase needs a preposition to link the release to the actions; however, from the visible dropdown options for later blanks, we focus on the visible dropdowns:
2. First visible dropdown (after "to survive"): The sentence connects forest loss to CO₂ increase, so "Since" is correct as it introduces the cause (forest depletion) for the effect (CO₂ surge).
3. Second visible dropdown (after "carbon dioxide in the air"): This links the CO₂ surge to forest depletion, so "due to" (logical connector for cause-effect) fits.
4. Third visible dropdown (after "of forests"): This introduces other parallel factors, so "Similarly" is correct to show additional contributors.

Answer:

1. First blank (after "atmosphere"): through
2. Second blank (after "to survive"): Since
3. Third blank (after "air"): due to
4. Fourth blank (after "forests"): Similarly

Full completed text:
Global warming is a result of an increase in greenhouse gases. Greenhouse gases are released into the atmosphere through deforestation and combustion of fossil fuels.
Deforestation is a major contributor to global warming. Forests help to maintain the levels of oxygen in the air that make it possible for us to survive. Since there has been a surge in the levels of carbon dioxide in the air due to the depletion of vast stretches of forests, Similarly other factors, such as the release of CFCs from refrigerators and pollutants from industries into the atmosphere, are also responsible for global warming.