Erreur mysql_real_escape_string()

Bonjour,

Sachant que j'utilise la dernière version de wampserveur, voici mon script register.php :

<?php
      
      if(isset($_POST['submit']))
	    {
		         $sexe = mysql_real_escape_string(htmlentities($_POST['sexe'])); 
		        $pseudo = mysql_real_escape_string(htmlentities($_POST['pseudo']));
				$password = mysql_real_escape_string(htmlentities($_POST['password']));
				$repeatpassword = mysql_real_escape_string(htmlentities($_POST['repeatpassword']));
				$email = mysql_real_escape_string(htmlentities($_POST['email']));
				$apropos = mysql_real_escape_string(htmlentities($_POST['apropos']));
				$situation = mysql_real_escape_string(htmlentities($_POST['situation']));
				
				if(empty($pseudo))
			    {
				  $errors[] ="Veuillez saisir un pseudo";
				}
				
				if (empty($password))
				{
				  $errors[] ="Veuillez saisir un password";
				}
				
				if($password != $repeatpassword)
				{
					$errors[] = "Vos deux password doivent être identiques";
				}
				
				if(!filter_var($email,FILTER_VALIDATE_EMAIL))
				{
					$errors[] = "Votre adresse email n'est pas correcte";					
				}
				
				if(empty($apropos))
				{
					$errors[] = "Veuillez vous décrire en quelques lignes";				
				}
				
				if(!empty($errors))
				{
					foreach($errors as $error)
					{
						echo "<div class='error'>".$error."</div>";
					}
				}
	    }
<code>?>

<form method="POST" action="">

   <label for='sexe'>Sexe</label>
   <select name="sexe">
	          
	          <option value="Homme">Homme</option>
              <option value="Femme">Femme</option>			  
	</select><br /><br/>
	
	<label for='situation'>Situation</label>
	<select name="Situation">
	          
	          <option value="Célibataire">Celibataire</option>
              <option value="En couple">En couple</option>	
			  <option value="Divorcé(e)">Divorce(e)</option>
			  <option value="Veuf(ve)">Veuf(ve)</option>
	</select><br /><br/>
	
	<label for="pseudo">Votre pseudo : </label>
	<input type="text" name ="pseudo"><br />
	
	<label for="password">Votre password : </label>
	<input type="password" name ="password"><br />
	
	<label for="repeatpassword">Repetez votre password : </label>
	<input type="password" name ="repeatpassword"><br />
	
	<label for="email">Veuillez saisir votre email : </label>
	<input type="text" name ="email"><br />
	
	<label for="apropos">A propos de vous </label>
	<textarea rows="6" cols="30" name="apropos"></textarea><br /><br />
	
	<input type="submit" value="S'inscrire" name="submit">
	
</form>

<a href='index.php?page=login'>Retournez à la page de connexion</a>

</code>

_____________________
quand je vais dans "http://localhost/rs/index.php?page=register", ils m'affichent 2 erreurs :

-Deprecated: mysql_real_escape_string(): The mysql extension is deprecated and will be removed in the future: use mysqli or PDO instead in C:\wamp\www\rs\pages\register.php on line 7

-Notice: Undefined index: situation in C:\wamp\www\rs\pages\register.php on line 13

Que faire svp ? #Débutant