Explanation:
Fixed> materials for used production, machinery
Variable> Employee salary, wages, rent
Answer:
Internal: employees, raw materials, machinery
External: odor arising from production, by-products
Answer: sponges are the cleaners of the water around the corals , coral feeders , and healers in a sens
frequency✧C
wavelength✧A
wave speed✧D
wave period✧E
amplitude✧B
i'm not sure if they are all correct so sorry ✧
I think this would help
Good luck!
have a great day ahead:)
D is the correct answer
ur welcome :3