Soil, because a fertile soil nourishes the seedlings well
the black bean grows faster because the seed germanates faster
Sand ofcourse
If you think it does then your right
No, I don't think so.
soil
They don't grow better in sand they need more attention than in soil. They don't grow better they will survive but need more attention than in soil.
Yes. Try them in both.
the wind blew the sand on top of growing plants which helps the sand stay together and more and more sand keeps on adding on and moree plants grow there for it gets bigger and bigger
You put the cactus on sand. There is no seed required. Also know they cannot grow right next to each other.
Depends on the seeds. If I'm sowing seeds in a greenhouse type situation, I typically use a standard potting mix (1 part each good garden soil, sand and compost) topped with about 1/4" of plain sand, sow the seed, then top with a little more sand.
Grain of sand is bigger
sand+life=seeds