Ketosis is a condition of acidosis resulting from: high blood glucose. Excessive fat metabolism. High insulin levels. Excessive corticosteroid treatment.

Ketosis is a condition of acidosis resulting from excessive fat metabolism.

Here's a step-by-step explanation:

1. Ketosis is a metabolic state characterized by raised levels of ketone bodies in the body tissues.

2. This condition usually occurs when the body is metabolizing fat at a high rate and converting fatty acids into ketones.

3. Ketosis can occur during periods of fasting, carbohydrate restrictive diets, starvation, prolonged intense exercise, alcoholism or in untreated (or inadequately treated) type 1 diabetes mellitus.

4. It's not caused by high blood glucose, high insulin levels, or excessive corticosteroid treatment. These conditions are related to different metabolic states.

5. High blood glucose and high insulin levels are associated with diabetes, but they do not cause ketosis unless insulin treatment is inadequate.

6. Excessive corticosteroid treatment can lead to increased blood glucose levels, but not ketosis.

So, the correct answer is: Ketosis is a condition of acidosis resulting from excessive fat metabolism.