| Pepsin, for one | 15 |
| Biochemical catalyst | 20 |
| Pepsin, e.g. | 12 |
| DNA polymerase, e.g. | 20 |
| Digestive protein | 17 |
| Breakdown cause? | 16 |
| Biological food processor | 25 |
| Biological catalyst | 19 |
| What '-ase' may signify | 31 |
| Trypsin, e.g. | 13 |
| Sucrase, e.g. | 13 |
| Substance essential to life | 27 |
| Saliva component | 16 |
| Pepsin or lactase | 17 |
| Lipase or amylase | 17 |
| It often ends in "ase" | 32 |
| It may cause a breakdown | 24 |
| It causes a breakdown | 21 |
| Fermentation substance | 22 |
| Digestive chemical | 18 |
| Complex protein | 15 |
| Cell product | 12 |
| Cause of a breakdown | 20 |
| Catalytic protein | 17 |
| Catalyst in yeast, for one | 26 |
| Digestion aids | 14 |
| They cause breakdowns | 21 |
| Organic catalysts | 17 |
| They help digest food | 21 |
| Some juices | 11 |
| Pepsins, e.g. | 13 |
| Pepsin, trypsin, etc. | 21 |
| Pepsin and trypsin | 18 |
| Pepsin and rennin, for two | 26 |
| Many end with '-ase' | 28 |
| Agents of biochemical change | 28 |
| Tertiary Period epoch | 21 |
| Geological epoch | 16 |
| Geologic epoch | 14 |
| Epoch of the Tertiary Period | 28 |
| Dawn-of-mammals epoch | 21 |
| Epoch when mammals arose | 24 |
| Epoch in which mammals became dominant | 38 |
| Epoch in which modern mammals first emerged | 43 |
| Epoch in which mammals arose | 28 |
| One of the epochs | 17 |
| Of a Tertiary epoch | 19 |
| Epoch in the Tertiary Period | 28 |
| Epoch between Paleocene and Oligocene | 37 |
| Certain geologic epoch | 22 |
| Tertiary Period part | 20 |
| Tertiary epoch | 14 |
| Occurring 40 to 55 million years ago | 36 |
| Epoch with lots of fish | 23 |
| Epoch when modern mammals appeared | 34 |
| Epoch when mammals began | 24 |
| Epoch when mammals appeared | 27 |
| Epoch when bats first appeared | 30 |
| Epoch that saw the dawn of modern mammals | 41 |
| Epoch that saw the advent of mammals | 36 |
| Epoch of the mammal | 19 |
| Epoch of mammals' appearance | 32 |
| Epoch of 50 million years ago | 29 |
| Epoch in which modern mammals emerged | 37 |
| Epoch characterized by the rise of mammals | 42 |
| Epoch 50 million years ago | 26 |
| Dawn horse epoch | 16 |
| Certain geological epoch | 24 |
| Cenozoic epoch | 14 |
| A Tertiary Period epoch | 23 |
| Want ad letters | 15 |
| Job ad letters | 14 |
| Classified letters | 18 |
| Classified ad inits. | 20 |
| "We hire everybody," briefly | 38 |
| Want ad initials | 16 |
| Job posting abbr. | 17 |
| Inits. in the classifieds | 25 |
| Employment ad letters | 21 |
| Classified letters, perhaps | 27 |
| Abbr. in a job ad | 17 |
| Want-ad letters used in hiring | 30 |
| Want-ad initials | 16 |
| Unbiased hirer's abbr., in ads | 34 |
| Unbiased hirer, in ads | 22 |
| Unbiased hirer, briefly | 23 |
| Nondiscriminatory business abbr. | 32 |
| No-bias-in-hiring abbr. | 23 |
| Many a hirer: Abbr. | 19 |
| Letters in a help wanted ad | 27 |
| Letters for a nondiscriminatory hirer | 37 |
| Letters for a nondiscriminating hirer | 37 |
| Job-ad letters | 14 |
| Job spec. | 9 |
| Initials in the want ads | 24 |
| Fair hiring practice, initially | 31 |
| Fair hiring inits. | 18 |
| Fair hiring abbr. | 17 |
| Fair hirer's abbr. | 22 |
| Fair hirer, in a classified (Abbr.) | 35 |