Mono Green Landfall ramps into huge threats like Mossborn Hydra and Mightform Harmonizer that scale well past our bounce and 2-mana-value-locked removal, so we need unconditional damage. Sunspine Lynx's enters-the-battlefield damage punishes their many nonbasic lands (Escape Tunnel, Fabled Passage) while also shutting off their incidental lifegain, making it a strong proactive threat. Fire Magic's Fira mode for 2 additional mana cleanly kills Llanowar Elves and Sazh's Chocobo before they grow, and scales to Firaga against bigger mana dorks later. Bounce Off is too slow against a ramp deck that will just replay bigger threats, and Spell Snare whiffs on most of their relevant spells which cost more than 2. Keep pressuring early before their ramp overtakes us.