Do we say one or one in front of these words

It's not easy to write and speak French well, there are at least 100000000 rules. In order to give you a helping hand, we decided to present you 15 words in French that we do not know the grammatical genre. Do we use one or one before the word testicle, escape route, afternoon…? Are you ready to take the quiz? (via Topito)

1. Tentacle

2. Dumbbell

3 Oasis

4. Testis

5. Escape

6. Intermission

7. Orbit

8. Balance

9. Afternoon

10. Alveolus

11. Petal

12. Anagram

13. Ovum

14. Lightning

15. Cigarette

answers:

1. We say “one” / 2. We say “one” / 3. We say “one” / 4. We say “one” / 5. We say “one” / 6. We say “one” / 7. We say "a" / 8. We say "un" / 9. We say "un". And also “a” / 10. We say “a” / 11. We say “a” / 12. We say “a” / 13. We say “a” / 14. We say “a” / 15. We say " a "