Hi there All the answers that have been given are correct. In order to clarify, you can take this one into account too: To construct simple present questions, while using “do” or “does”, you need a MAIN VERB. For example: do you LIKE pizza? Does he SPEAK English? On the other hand, when you use “to be verbs”, am/is/are, in constructing simple present questions, there is no need for a main verb. For example: Is the Earth round? Are you from the US? Having said that, in your sentence we have a main verb “eat”, therefore there is a need for an auxiliary verb, “do”. Peace :)

Good questions. You can say it two ways: "What do the horses eat?" (Какова их диета?) or "What are the horses eating?" (Что они едят сейчас?)

When you ask "what do the horses eat?" You are asking a question in simple present tense which means what do normally eat. It's a general question. Answer can be anything what horses eat. Or you can ask what are the horses eating? This is in present continuous tense which means what they are eating now? I suggest you to learn English tenses to get a better understanding.

Help you!

Eat* not meat)