| Radiasi adaptif | |
| Radiasi Non-Pengion | |
| Radiasi Pengion | |
| Rahim | |
| Rantai Pengangkut Elektron | |
| Reaksi Eksergonik | |
| Reaksi Endergonic | |
| Rekombinasi Genetik | |
| Relung Ekologis | |
| Reproduksi aseksual | |
| Reproduksi seksual | |
| Reseptor | |
| Reseptor NMDA | |
| Respirasi Anaerobik | |
| Respirasi Eksternal | |
| Respirasi Internal | |
| Respirasi Seluler | |
| Retikulum endoplasma | |
| Retikulum endoplasma halus | |
| Retikulum Endoplasma Kasar | |
| Ribosom | |
| Rigor Mortis | |
| Rimpang | |
| RNA Polimerase | |
| RNA ribosom | |
| Rongga dada | |
| Rongga perut | |
| Rongga punggung | |
| Rongga tubuh | |
| Rongga Ventral | |
| Ruas | |
| Rumputan |