Ureotelic excretion is the process of excreting waste as urea, a nitrogenous compound that is less toxic than ammonia. This type of excretion is found in both mammals and amphibians.

Mammals:
- Mammals, such as humans, dogs, and cows, excrete waste products through their kidneys in the form of urea. The urea is produced in the liver through the breakdown of amino acids, which are the building blocks of proteins.
- The urea is then transported to the kidneys, where it is filtered out of the blood and excreted in urine. The urine is composed of water, urea, and other waste products.
- Ureotelic excretion allows mammals to efficiently remove nitrogenous waste from their bodies while conserving water.

Amphibians:
- Amphibians, such as frogs and salamanders, also excrete waste as urea. However, they have a more complex excretory system compared to mammals.
- Amphibians have a pair of kidneys, called the mesonephric kidneys, which filter waste products from the blood. The waste is then excreted as urine, which contains urea and other waste substances.
- In addition to the mesonephric kidneys, amphibians also have a pair of small structures called the nephrostomes, which help in the filtration of waste products.

Coelenterates:
- Coelenterates, which include jellyfish and sea anemones, do not have a specialized excretory system. Instead, they rely on diffusion to eliminate waste products.
- Coelenterates have specialized cells called cnidocytes, which contain nematocysts that are used for defense and capturing prey. The waste products from these cells are eliminated through diffusion into the surrounding water.

Conclusion:
Given the information above, it is clear that ureotelic excretion is found in both mammals and amphibians. Mammals have a more efficient excretory system, while amphibians have a simpler system. Coelenterates, on the other hand, do not have a specialized excretory system and rely on diffusion for waste elimination. Therefore, the correct answer is option D - Both (1) Mammals and (2) Amphibians.