<apex:pageBlockSectionItem >
                <apex:outputLabel value="Products"/>
                <apex:outputPanel >
                  <apex:selectList value="{!products}" size="1">
                   <apex:actionSupport event="onchange" action="{!selectProduct}" rerender="Selectproducts"/>
                    <apex:selectOptions value="{!Items}"/>
                    </apex:selectList>
                    </apex:outputPanel>

            </apex:pageBlockSectionItem>

            <apex:pageBlockSectionItem >
                <apex:outputLabel value="Question ID"/>
                <apex:inputField label="Qusetion ID" value="{!USOT_Questions__c.Qusetion_ID__c}"/>
            </apex:pageBlockSectionItem>

            <apex:pageBlockSectionItem >
                <apex:outputLabel value="Question"/>
                <apex:inputField label="Question" value="{!USOT_Questions__c.Question__c}"/>
            </apex:pageBlockSectionItem>



            <p>Questions List </p>

            <apex:pageblocktable value="{!Queslist}" var="q" id="Selectproducts" >  <apex:column value="{!q.Qusetion_ID__c}"/>
                <apex:column value="{!q.Question__c}"/>
            </apex:pageblocktable>
        </apex:pageBlockSection>

    </apex:pageBlock>
</apex:form>