Where do ostriches lay their eggs?

ON the ground

I find this answer confusing. to say that an ostrich lays it eggs 'in' the ground in incorrect. that suggests that is buries the eggs by digging a hole like a tortoise. I live in SA and are familiar with Ostriches. they lay their eggs 'on' the ground, in a nest. Both parents sit on the nest ( on the ground) and keep the eggs warm. The answer 'in' the ground is incorrect.