21. So low air temperatures and low humidity are the optimal conditions for making snow. 22. Under optimal conditions , it can destroy an entire orchard in a single growing season. 23. NHDC itself can stay foodsafe for up to five years when stored in optimal conditions . 24. The tree grows rapidly under optimal conditions , easily reaching 70 feet with substantial spreading branches. 25. Trees grow slowly to, or rarely in optimal conditions . 26. The plasma is burnt at optimal conditions , and any significant change will quench the reactions. 27. Cooking rice in a pressure cooker allows the rice to cook under more optimal conditions . 28. Under these optimal conditions , the researcher has control over the intervention and how it is delivered. 29. Under optimal conditions , northern red oak is fast growing and a 10-year-old tree can be tall. 30. Increasing the urine pH to around 6.5 provides optimal conditions for dissolution of uric acid stones.