| ALARMBELL | A category encompassing marine life initially provides warning |
| FEEFIEFOEFUM | Sounds like husband of 7 down provides warning for English Jack (3,3,3,3) |
| DISCOVERY | After spinner's six deliveries, yorker initially provides breakthrough ... (9) |
| CORALREEF | Underwater ecosystem, home to some 4,000 species of marine life (5,4) |
| PLACENTAL | Like a category of mammals |
| LABELLING | Assigning to a category (9) |
| ROCKPOOLS | Puddles of trapped sea water forming mini ecosystems or habitats for limpets, periwinkles, anemones, starfish and other marine life (4,5) |
| SEAURCHIN | Marine life form hurricanes unsettled ___ number finally destroyed (3,6) |
| UNDERSEAL | Marine life at first's given elemental protection (9) |
| SHELLFISH | She'll take marine life to be cockles and mussels (9) |
| BARNACLES | Marine life in photo (9) |
| OILSLICKS | Hazards for marine life |
| GRADE | A category of a listed building; a music exam; or, meaning "step", word originally used in English as a unit of measurement of angles, now for a particular level of quality, rank etc (5) |
| EXTOL | Praise leaving one down on life initially (5) |
| VITAL | Very important to all life, initially (5) |
| IRIS | Irish Rugby Injury Surveillance initially provides the answer (4) |
| PLOT | This aspect of The Mousetrap initially provides lots of tension (4) |
| MESH | Material's evenly spaced holes initially provide a net-like fabric (4) |
| TYPE | A category or class with shared characteristics; a device on a coin or a medal; or, little metal blocks bearing letters for printing collectively (4) |
| OVERLAID | Covered past life initially with relief (8) |
