Human Excretion and Kidney Physiology

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.

Rotifers are microscopic aquatic animals belonging to phylum rotifera. They eat dead bacteria, algae and protozoans. The excretory structures of rotifers are Flame cells. The flame cells function like a kidney, removing nitrogenous waste.

Birds excrete nitrogenous wastes as uric acid in the form of a pellet or paste with a minimum loss of water. Therefore they are called uricotelic animals. 

(A) The process of excreting ammonia is Ammonotelism. Many bony fishes, aquatic amphibians and aquatic insects are ammonotelic. 

Ureotelic organisms produce ammonia as a metabolic byproduct, which is then converted into urea in the liver via the urea cycle. Therefore, the statement that ammonia is not a product of metabolism in these organisms is false.

The renal gland is a relatively wide tube opening from a sac (the pericardium) surrounding the heart, at one end, and to the mantle cavity (effectively to the exterior) at the other. The anatomical form of the renal gland varies from one class of molluscs to another.

The Bowman's capsule and the glomerulus together constitute the malpighian corpuscle (pygmalion corpuscle or renal corpuscle). The malphigian corpuscles were first described by Morcello Malpighi in the year 1966.