Answer:
At the base of Actinopterygii
*This is a unique characteristic of this group.
Explanation:
A peculiar characteristic organ observed in ray-finned fish (as well as in Sarcopterygii, or lobe-finned fish) but not in cartilaginous fish like shark is the swim bladder.
This organ is often described to be a sac containing gas. It helps these set of fish adjust its buoyancy and its position in the water by regulating the concentration of gas present in it.
The swim bladder is formed as a pouch coming off the embryonic digestive tract, and in chondrosteans and holosteans, with a set of teleosts e.g. the eels, it maintains an open pathway to the esophagus. In majority of the bony fish, the swim bladder is totally sealed off, as gas levels in their swim bladder are regulated by producing gas into the bladder via a network of capillaries, the rete mirabile (Latin word for "marvelous net").
The swim bladder is homologous to the lungs of tetrapods. Since they are formed in the same vein. Few fishes that have an open swim bladder employs it as a breathing organ.
Human chorionic gonadotropin (hCG) is secrete by the embryo early in pregnancy to keep the corpus luteum for dying. This positive feedback will maintain the corpus luteum, which secretes Progesterone and Estrogens throughout pregnancy, in order to keep the endometrium well to nourish the embryo/fetus.
Basically all of the choices given are failure of negative feedback mechanisms to maintain homeostasis. The correct option among all the options that are given in the question is the last option or option "E". I hope that this is the answer you were looking for and it has come to your help.
The answer is d I juss took the test
The ability to reproduce
The ability to respond to stimuli .
The 2nd one may be a bit confusing but people who do not respond to stimuli eg they have CIPA or are blind or deaf can still survive
