deserve If you say that a person or thing deserves something, you mean that they should have it or receive it because of their actions or qualities.
observe If you observe a person or thing, you watch them carefully, especially in order to learn something about them.
reserve If something is reserved for a particular person or purpose, it is kept specially for that person or purpose.
conserve If you conserve a supply of something, you use it carefully so that it lasts for a long time.
preserve If you preserve a situation or condition, you make sure that it remains as it is, and does not change or end. If you preserve something, you take action to save it or protect it from damage or decay.