javascriptにてクリックしても反映されないです

result0のところに◯か×を表示させたいのですが、if文を使っても反映されません。
間違っている部分があればご指摘お願いします。

html
1<!DOCTYPE html>
2<html lang="ja" dir="ltr">
3<head>
4  <meta charset="utf-8">
5  <link rel="stylesheet" href="kate2.css">
6  <form action="kate3.html" method="POST">
7  <title>Eラーニング</title>
8</head>
9<body>
10  <div class="xia"></div>
11  <label class="answer">
12  <label>1番<input type="radio" id="answer1"name="answer1" value="1" ></label>
13  <label>2番<input type="radio" name="answer1" value="2"></label>
14  <label>3番<input type="radio" name="answer1" value="3"></label>
15</label>
16  <p class="result" id="result0"></p>
17  <div class="xia2"></div>
18  <label class="answer">
19  <label>1番<input type="radio" name="answer2" value="1"></label>
20  <label>2番<input type="radio" name="answer2" value="2"></label>
21  <label>3番<input type="radio" name="answer2" value="3"></label>
22  <label>4番<input type="radio" id="answer2"name="answer2" value="4"></label>
23</label>
24  <p class="result" id="result1"></p>
25  <div class="xia3"></div>
26  <label class="answer">
27  <label>1番<input type="checkbox" name="answer3" value="1"></label>
28  <label>2番<input type="checkbox" id="answer3"name="answer3" value="2"></label>
29  <label>3番<input type="checkbox" id="answer3_1"name="answer3" value="3"></label>
30  <label>4番<input type="checkbox" name="answer3" value="4"></label>
31</label>
32  <p class="result" id="result2"></p>
33  <h3>採点</h3>
34  <p><span id="total"></span></p>
35  <input  type="button" id="saiten" value="採点"　onclick="click"></button>
36  <input type="submit"　value="次へ"/>
37<input type="reset" onclick="history.back()" value="キャンセル"/>
38</form>
39<script type="text/javascript" src="kate2.js"></script>
40</body>
41</html>
42

javascript
1var answer1=document.getElementById("answer1");
2var answer2=document.getElementById("answer2");
3var answer2=document.getElementById("answer3");
4var answer2=document.getElementById("answer3_1");
5var result0=document.getElementById("result0");
6var result1=document.getElementById("result1");
7var result2=document.getElementById("result2");
8var total=document.getElementById("total");
9var saiten=document.getElementById("saiten");
10
11var aaa = function () {
12if(answer1.checked) {
13result0.innerHTML="◯";
14}else {
15  result0.innerHTML="◯";
16}}
17

css
1footer {
2  margin-top: 40px;
3}
4.flex {
5  display: flex;
6  align-items: center;
7}
8.result {
9  margin-left: 1em;
10  padding: 5px;
11  min-width: 100px;
12  min-height: 1em;
13  background: #eee;
14}
15.xia,.xia2,.xia3{
16  border: 1px solid #000000;
17  width: 830px;
18  height: 70px;
19}
20p{
21  width: 29px;
22}
23