1838
Theodor Schwann (1810-1882)
In 1838, Schwann and Matthias Jakob Schleiden (1804-1881) developed the "cell theory." Schwann went on and published his monograph Microscopic Researches into Accordance in the Structure and Growth of Animals and Plants in 1839.
They have an adaptation called trigger hairs.
That would be a water habitat because of the fact that water would be the important part of the marine life, therefore, it is a fundamental unit of life.
Answer:
I don't get what you are trying to ask
Some of the eggs might not make it to there destination that is required to reproduce.