Given scientific fact as input, generate the question from this fact such that it can be answered from the input.

Sexual reproduction, in general, relies on sets of cells that are precursors for eggs and sperm.
What kind of reproduction, in general, relies on sets of cells that are precursors for eggs and sperm?

In invertebrates group of animals several forms of asexual reproduction are found.
In what group of animals several forms of asexual reproduction are found?

Cardiac veins parallel the small cardiac arteries and generally drain into coronary sinus.

Cardiac veins parallel the small cardiac arteries and generally drain into what sinus?