Since the death rate is higher than the birth rate we can assume that it will be negative. 5-15 is -10 for their life. immigration is also lower than the emigration. 2-4 is -2. adding -2 and -10 will give us -12, hope this helps.
The pair of characteristics that one must use to classify a fish is the presence of jaw and skeleton type. Agnatha fishes are also called jawless fishes and they lack bony skeletons. Cartilaginous fishes are composed of cartilage skeletons. Bony fishes have bony skeleton structures.
