Why is the alarm calling of the vervet monkey an example of advanced communication?

the response is innate and stays consistent over time.
the response is innate and varies over time.
the response is learned and varies over time.
the response is learned and stays consistent over time.

Which of the following best describes the expensive tissue hypothesis? brains require more energy, so the gut had to be reduced, and larger brains and tool use led to higher quality diets. increasing body size means that homo neanderthalensis had to include more fat in its diet. brains require more energy, so the gut had to be reduced as brains got bigger. brains require more fat, so the gastrointestinal viscera (gut) had to expand, and hands were needed to acquire more food.