JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.1.1/jquery.min.js"></script>

<body>
    <div class="control-group nested-fields" style="border: 1px solid red">

          <div class="field col-xs-3">
        <label for="person_carros_attributes_0_marca_id">Marca</label>
        <select id="marcas_select" class="form-control" name="person[carros_attributes][0][marca_id]"><option value="">Selecionar marca</option>
            <option value="1">Fiat</option>
            <option value="2">Chevrollet</option>
            <option value="3">Ford</option>
        </select>
          </div>
        <br>
          <div class="field col-xs-3">
            <label for="person_carros_attributes_0_modelo_id">Modelo</label>

            <select id="modelos_teste" class="form-control" name="person[carros_attributes][0][modelo_id]"><option value="6">Uno</option>
                <option value="7">Palio</option>
                <option value="8">Siena</option>
                <option value="9">Prisma</option>
                <option value="10">Onix</option>
                <option value="11">Cobalt</option>
                <option value="12">Ka</option>
                <option value="13">Toro</option>
            </select>
          </div>
    </div>

JavaScript

$(document).on('change', ':focus', function(evt) {
    $('#modelos_teste').css('background-color', 'yellow');
});