sql在单选按钮中显示数据

i have few answers to quiz stored in db. i am displaying them as radio buttons on form like this

$row = mysql_fetch_array(mysql_query('select * FROM quiz order by rand() limit 1'),MYSQL_ASSOC);

<?php
        foreach ($row as $key => $value) {
            echo "<input type='radio' name='answer'>".$value."</input><br />";
        }
    ?>

but when i post this form the echo on other end is not getting a radio button answer i selected. please help

echo "<input type='radio' name='answer' value='".$value."'>".$value."</input><br />";

The only things that I can see is that

a) There is no form tag outside of the radio

b) You aren't giving the radio a value such as:

 <input type='radio' name='answer' value="1"> Male
 <input type='radio' name='answer' value="2"> Female