Abiotic means non-living. So the correct answer is "the lack of oxygen in coastal waters"
One characteristic of life is that living things have different levels of organization
-They have both molecular and cellular organization
- They must have the ability to organize simple substances into complex ones.
- They organize cells at several types of levels, namely:
(a) Tissue- a group of cells that perform a common function
(b) Organ - A group of tissues that perform a common function.
(c) Organ system- a group of organs that perform a common function.
(d) Organism- any complete living thing.
They walk on all fours , they can’t swim , shorter lifespan, extra chromosomes
The presence of vertebral column or notochord at any stage of life in any organism is the characteristic of vertebrate.
Explanation:
An animal is vertebrate if it fulfils the following criteria:
Presence of vertebral column or notochord.
Presence of endoskeleton or backbone.
The spinal cord runs above the vertebral column.
Humans embryo has notochord which becomes a vertebral column.
The alimentary canals end in the anus.
Mouth is present ta the anterior side of the vertebrate.
Have legs, fins or wings for movement.
Presence of a nervous system and sensory organs.
Presence of skin, lungs or gills.
Presence of a circulatory system.
Vertebrates include fish, amphibians, reptiles, birds and mammals.
