i think i'm turning japanese: what letter ends all japanese words not ending with a vowel?

Questions

Certain ---------- emit a light so penetrating that it can pass through flesh and wood.?

Certain fireflies emit a light so penetrating that it can pass through ---------- and wood.?

Certain fireflies emit a light so penetrating that it can pass through flesh and---------- .?

Certain ---------- can be frozen solid then thawed, and continue living.?

Certain species of male butterflies produce scents that serve in attracting females during---------- .?