environmental factors affecting marketing activities
Externally
Heat
Temperature and moisture.
without jaws
skin
Agnatha, also known as jawless fish, lack jaws and scales. They have a cartilaginous skeleton, a round mouth, and a single nostril on their head. Agnatha are also known for their ability to produce slime as a defense mechanism.
by the gill slits
with gills; they're fish!
Class Agnatha
jawless fish. not very common today, but they were in the past.
I don't know but i will do some research...