You are using some javascript to make your select list look different. It is using a <ul> and <li> tags to do that behind the scenes, so your list is picking up those classes from your CSS making it display that way. You can overwrite it with css like:
.chose-us-area .info .nice-select ul {
margin-top: 0;
}
.chose-us-area.item-half .info .nice-select li {
float: none;
width: 100%;
margin-top:0;
}