Yes, but what is balanced for animals is different than what is balanced for people. For example, a house cat eats meat but no vegetables.
For a heathly lifestyle 
Its very good to have a well balance diet because it makes you feel more alive and its 5x more times healthier than normal diets. But to answer you question no you do not need to take a well balance diet ( unless you want to be skinny or super fit)
we need a balance diet because it help keep as healthy and well, fight infections and give as plenty of energy.
Animals could survive without frogs if they have any other kind of diet but while that some animals need to eat fles to survive just like an anteater need ants in their diet.
Yes, but they need to be careful. The biggest problem is getting all the essential amino acids; all animals have them but not all plants. But it doesn't take much, half a can of tuna a day is plenty.
almost all animals need salt in their diet
Balanced diet
Animals need lots if things to survive. Example food and water, some might even need diet's to maintain there body weight and health.
animals need fat In their diet inorder to survive, unlike us they don't get their fats from things like chocolate, if they didnt consume the fat they need they would most likely die out, for example, lions;they need power and speed to catch pray, they get the engery to pounce on their pray from the fat in there body, the energy that comes from their diet is stored away,
a balance diet is one with three or more food groups in your meal or diet. c;
To be a footballer, you need to train hard, eat a right diet,and balance out your food, you need to have either or both stamina and speed, strengths...
Except for very overweight and obese teens, average teens don't need to go on diet. They just have to eat healthy and balance meals.