Human Excretion and Kidney Physiology

Cyclostomes are the organisms which belong to the group of chordates. These are the jawless fishes. The group also includes the lampreys and hagfishes. They have rounded mouths that lack jaws. The water keeps on cycling through the open mouth which cannot be closed due to lack of jaws. 

Hyperbilirubinemia is excessive bilirubin in blood. It is also called jaundice. It leads to deposition of bilirubin in mucous membrane, sclera and skin so that the patient looks yellow or icterus. Urine is yellow. It is caused by obstruction in bile duct, excessive hemolysis, or viral infection.

On the basis of development, there three types of kidneys as pronephric kidney, mesonephric kidney and the metanephric kidney.

The excretory product of freshwater fishes is 'ammonia'.

• Amphibians have mesonephric type of kidneys which are primitive compared to metanephric kidneys. 
• Mesonephric kidneys do not have nephrons but their nephrons do not contain a loop of Henle.

The original nephrostomes remain in the adult frog on the ventral face of the kidney as ciliated peritoneal funnels. These convey coelomic fluids directly into the blood sinuses of the kidney. They are regarded as accessory excretory structures.

Mammals like humans and rabbit, many terrestrial amphibians and marine fishes mainly excrete urea and are called ureotelic animals. Ammonia produced by metabolism is converted into urea in the liver of these animals and released into the blood, which is filtered and excreted out by the kidneys. Some amount of urea may be retained in the kidney matrix of some of these animals to maintain a desired osmolarity.

The metanephric kidneys are a paired compact organ whose functional units are nephrons. The nephrons filter initial urine from the blood, reabsorbing water and nutrients, and secrete wastes, producing the final urine, which is expelled. In adult Frog, The kidney is Metanephros.

Sea gulls are marine birds belonging to the family Laridae. They drink salt water as a result to maintain their osmotic balance they excrete salts through nasal gland or salt gland present in the nostrils and assist kidney in maintaining electrolyte balance.

Amoeba is a fresh water unicellular organism. In amoeba the excretory waste is ammonia. The excretory waste present in the cytoplasm is collected by contractile vacuole then this excretory waste i.e NH$ _3$ is excreted through plasma membrane by diffusion.

The frogs which are highly aquatic belongs to the genus xenopus. They are usually found in lakes, rivers, swamps. The xenopus excretes ammonia as nitrogenous waste hence ammonotelic.

For many chordates, the urinary system is a critical component of the excretory system. It is made up of organs such as the kidneys and bladder, structures such as a urethra or cloaca, and even arteries such as the aorta. The urinary system is responsible for both creating and excreting urine, which it does to regulate the amount of water and solutes within the body. Amazingly enough, the urinary system also works closely with hormones in your body that signal when you start to become dehydrated or when there is too much fluid in your body.

So, the correct option is 'All chordates'.

Hepatopancreas is not an excretory organ of vertebrates. It is a glandular excretory organ present in many invertebrates like arthropods and molluscs. It shows functions similar to liver and pancreas of vertebrates.

Salamander belongs to the phylum Chordata and class amphibia. Just like humans, the salamander has two kidneys which excrete urea as the nitrogenous waste product. Two kidneys are extremely important in excreting nitrogenous waste, and the urinary bladder stores waste in the form of urea before it is released into the environment.

Hydra is sessile and cylindrical in shape belonging to the phylum Cnidaria and class Hydrozoa. It has no specialized excretory organs hence excretion in hydra occurs by diffusion through the general body surface.