the different between call and apply in javascript

function sayColor(spre, ssuf) {alert(spre + this.color + ssuf);};  
var obj = new Object();  
obj.color = 'red';  
sayColor.call(obj, "this is ", " , a very nice"); # this is red a very nice  
sayColor( "this is ", " , a very nice"); # this is undefined a very nice  
sayColor.apply(obj, new Array("this is ", " a nice very")); #this is red a nice very