No, b) a common ancestor.
Well, considering it's an invertebrate, it probably eats scum off the ocean floor or small organisms.
They would probably have a way to liquify the organs of it's prey (or if it's an insect, not) and have a proboscis to suck out the liquids.
Epsom salt will not kill ants. However, they do not like salt, and will probably just move to another location.
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.
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
The body structure in all vertebrates indicated that these organisms originated from Precambrian times. This has to due with having a back bone.
probably cause current vertebrates have a backbone and ancient vertebrates ahd them to
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.
prokaryotic
Probably, the role of organisms is to consume the food from plants or animals.