Ion -select is not woking

i have created an ionic app with tabs template. i have further added new pages to the app. but ion-select is not working on the newly generated pages. it does not shows the select options. However, when tested on the tabs pages, it works fine. Below is the code I am using on both pages…
ion-select slot=“end”
ion-select-option value=“f” Female ion-select-option
ion-select-option value=“m” Male ion-select-option
Any idea what could be probably missing?