Tafsir of Ya seen 36:72

وذللناها لهم

And We have subdued them unto them, Meaning, He has made them subdue them. So they are submissive towards them and do not resist them; even if a young child comes to a camel he can make it kneel down, and if he wants to, he can make it stand up and can drive it, and it will meekly be led by him. Even if the train consists of a hundred or more camels, they could all be led by a young child.

فمنها ركوبهم ومنها يٲكلون

some of them they have for riding and some they eat. means, some of them they ride on their journeys, and use them to carry their burdens to all regions

ومنها يٲكلون

(and some they eat). means, if they want to, and they slaughter and sacrifice them