No, b) a common ancestor.
Vertabrates. The ones with vertabra and sharp teeth are called... dangerous. If I understand correctly, then the answer is this. Animals that have vertebrae are those that have a spine that helps support them, twist/bend/etc their bodies around in many different ways, allows the brain to send signals to different parts of their bodies, etc. Something like that. Animals like mammals, reptiles, birds, dinosaurs, etc.
Is a snake a reptile? Really? The snake is most definitely a reptile. In fact the snake is probably the most famous type of reptile in the world. Or the alligator/crocodile...
Organisms that do not ingest food, such as plants, obtain their nutrition through processes like photosynthesis. During photosynthesis, these organisms use sunlight, water, and carbon dioxide to produce sugars that serve as their energy source. Other organisms, like fungi, obtain nutrition through absorption by secreting enzymes that break down organic matter in their surroundings.
Likely competition. An organism's niche is the specific environment in which they live and procreate the best (which includes climate, food sources, places to live and escape from predators, etc.). An overlap of two different species niches means that the resources these organisms depend on are now in shorter supply. This means they must compete with the other organisms for survival
Different types of animals thrive in different enviroments. For example, marine organisms thrive in a wet, dark, habitat. Humans thrive better in a dry, fresh air, sunny habitat. There are different habitats so that all the different organisms on the planet will be able to survive. If there was only one type of habitat, many of the organisms on the planet would not exist.
The body structure in all vertebrates indicated that these organisms originated from Precambrian times. This has to due with having a back bone.
Fossils of vertebrates are similar to the bones of living vertebrates because they were once part of living organisms that shared similar anatomical structures and functions. Over time, the bones of vertebrates have undergone evolutionary changes, but many core features have been conserved due to their essential functions. This similarity allows paleontologists to make informed comparisons and infer the evolutionary relationships between ancient and modern vertebrates.
The earliest vertebrates were probably similar to lampreys or hagfish.
Birds.
the variation in the forms of adult vertebrates probably arose through mutations in dominant genes
Well vertebrates are organisms possessing a backbone. Humans have backbones, making them vertebrates. To my knowledge, there has never been a human born without a backbone, so I would argue that the answer is 100%. Actually, it's not really up for debate. The answer is 100%.
probably sudying sience and getting there masters dagree
Yes, all vertebrates (e.g. fish, amphibians, reptiles, mammals, birds) have red blood cells. There are probably other organisms that also have red blood cells. However insects and several other invertebrates have a blue copper based blood instead of the red iron based blood of vertebrates. Bur they do not have blue blood cells as the copper based compound these organisms is free in the blood instead of contained inside cells.
The best job for that would probably a biologists.
Yes, all vertebrates (e.g. fish, amphibians, reptiles, mammals, birds) have red blood cells. There are probably other organisms that also have red blood cells. However insects and several other invertebrates have a blue copper based blood instead of the red iron based blood of vertebrates. Bur they do not have blue blood cells as the copper based compound these organisms is free in the blood instead of contained inside cells.
The classification of Vertebrates is comprised of mammals, birds, reptiles, amphibians,rays and sharks, bony fish and cyclostomes (jawless fish like hagfish), so it would be difficult to say where the majority of vertebrates probably live. Perhaps the largest number would be in the seas.
prokaryotic