Formulário PHP não envia para o e-mail todos os dados

Boa tarde!

Olha eu baixei um form em php e na hora que envia ele coleta somente o e-mail e o nome, já tentei de tudo e não consigo fazer ele coletar o campo whats, Alguém pode dar uma olhadinha e me ajudar por favor?

<?php
/*
This first bit sets the email address that you want the form to be submitted to.
You will need to change this value to a valid email address that you can access.
*/
$webmaster_email = "adrianoncaldeira@gmail.com";

/*
This bit sets the URLs of the supporting pages.
If you change the names of any of the pages, you will need to change the values here.
*/

$imc = "imc.html";
$error_page = "error_message.html";
$calculadora_imc = "calculadora_imc.html";

/*
This next bit loads the form field data into variables.
If you add a form field, you will need to add it here.
*/

$email_address = $_REQUEST['email_address'] ;
$nome= $_REQUEST['nome'] ;
$whats = $_REQUEST['whats'] ;

/*
The following function checks for email injection.
Specifically, it checks for carriage returns - typically used by spammers to inject a CC list.
*/

function isInjected($str) {
 $injections = array('(\n+)',
 '(\r+)',
 '(\t+)',
 '(%0A+)',
 '(%0D+)',
 '(%08+)',
 '(%09+)'
 );
 $inject = join('|', $injections);
 $inject = "/$inject/i";
 if(preg_match($inject,$str)) {
 return true;
 }
 else {
 return false;
 }
}

// If the user tries to access this script directly, redirect them to the feedback form,

if (!isset($_REQUEST['email_address'])) {
header( "Location: $imc" );
}

// If the form fields are empty, redirect to the error page.
elseif (empty($email_address) || empty($nome) || empty($whats)) {

header( "Location: $error_page" );
}

// If email injection is detected, redirect to the error page.
elseif ( isInjected($email_address) ) {

header( "Location: $error_page" );
}

// If we passed all previous tests, send the email then redirect to the thank you page.
else {
mail( "$webmaster_email", "Calculo de IMC",

 $nome, "From: $email_address" );
header( "Location: $calculadora_imc" );
}
?>