State the order in which various parts of flower are arranged from outer side to inner side.

Each of the part of flower is arranged in a whorl on the receptacle. The four main whorls starting from outer side to inner side are as follows:

• Sepals: are the green outermost leaf like floral organs which protect the flower in bud stage and provide support to outer floral organs.
• Petals: are colored accessory floral organs which lie above sepals and they may also provide protection to centrally placed reproductive organs (stamens and carpel).
• Stamens: are located inside the corolla and are leaf-like appearance and are male reproductive part.
• Carpels are female reproductive part and are one or more in number and are located in the upper center of the flower

So, the correct answer is 'Sepals $\to$ Petals $\to$ Stamen $\to$ Carpel'