Complex sentence: Merlin (an acronym for' "Medical Emergency Relief, International"') is the only specialist UK charity which responds worldwide with vital health care and medical relief for vulnerable people caught up in natural disasters, conflict, disease and health system collapse.
Split into simpler sentences: Merlin (an acronym for' "Medical Emergency Relief, International"') is a UK charity which specialises in saving lives in times of crisis and rebuilding shattered health services worldwide. It provides vital health care and medical relief for vulnerable people caught up in natural disasters, conflict, disease and health system collapse.