Plastid.
There are several:TsunamiTornadoVolcanoLocusts
you have spaces for seven letters
There are seven life processes that tell us that animals and plants are alive. To help us remember them use: Mrs Nerg. The letters in it stand for the life processes - movement, reproduction, sensitivity, nutrition, excretion, respiration and growth.
Le Havre
lithosphere
Carbon- sixth element, contains six letters. Mars- fourth planet, contains four letters. Four- fourth number, contains four letters. Seven- seventh number, contains seven letters. September- ninth month, contains nine letters. Saturn- sixth planet, contains six letters. Fifth- fifth number, contains five letters.
Leather
Cheetah
Copters
seduces
bellhop
therein
therein
therein
bellhop
bellhop
The answer lies in the question. your required word is "seven letter", as it contains eleven letters.