Kidneys that can conserve water are essential to homeostasis because: a) some animals live in dry or salty environments. b) some animals drink water. c) urea is not soluble in water d) their cells will be unable to convert ammonia into urea if excess water is excreted

a) option is correct

Explanation:

Homeostasis is the way animals maintain a stable internal balance in their body and allows animals to function in the changing external conditions surrounding their body

The high salt concentration in the ocean means that salt will be constantly diffusing into the body of some animals

Water and salts can move through the gill membrane to maintain the balance

The kidneys are used to remove excess salts through their urine, which is quite concentrated

The concentrated urine is also due to the increase in a hormone (ADH) which causes more water to be reabsorbed by the kidneys