Answer the following questions with JavaScript: a. What is the DOM (Document Object Model)? Explain in your own words. b. Explain getElementById(), getElementsByTagName() and getElementsByClassName() ? Explain in your own words. c. What does this do? Explain in your own words. document.getElementById("main").innerHTML d. What does this do? Explain in your own words. document.body.style.backgroudColor = "papayawhip"