1. Compensation point is the level of light intensity at which the rate of photosynthesis is equal to the rate of cellular respiration in plants
2. At the compensation point:

If the rate of photosynthesis and rate of cellular respiration remain at the compensation point,the plants do not grow normally. This is because:

• The rate of photosynthesis is low 
• All glucose produced from photosynthesis are oxidised during cellular respiration
• The energy produced from cellular respiration only sufficient to support the daily use of plants
• No excessive energy for normal growth
• No excess storage food in plants