Where is this parameter being supplied with an argument?

Question

Here's an example from YDKJS Scope & Closures, with a couple of slight modifications:

var MyModules = (function Manager() {
    var modules = {};
    function define(name, deps, impl) {
        for (var i = 0; i < deps.length; i++) {
            deps[i] = modules[deps[i]];
        }
        modules[name] = impl.apply(impl, deps);
    }
    function get(name) {
        return modules[name];
    }
    function printMod() {
        console.log(modules);
    }
    return {
        define, get, printMod
    }
})();

MyModules.define("bar", [], function() {
    function hello(who) {
        return "Let me introduce: " + who;
    }
    return { hello };

});

MyModules.define("foo", ["bar"], function(b) { // What is passing an object into b here?
    console.log(b);
    var hungry = "hippo";
    function awesome() {
        console.log(b.hello(hungry).toUpperCase());
    }
    return { awesome };
});

var bar = MyModules.get("bar"); 
var foo = MyModules.get("foo");

I've analyzed this snippet and understand what's going on. The one question I have however is how does the parameter in the pointed out line get its value of an object with the hello function reference? Shouldn't b be getting assigned the deps array we've supplied in the line modules[name] = impl.apply(impl, deps); ? Can someone help me sort out this confusion? I've never really used the apply method before.