Fog is like an unambitious cloud. It occurs when a mass of air can't hold any more moisture, at the dew point. Various conditions can lead to the formation of fog, usually involving a change in temperature or humidity.
Seedless grapes can occur naturally as random mutations in which the seeds to do not develop properly. They can be propagated through cuttings and grafting. Selective breeding involved rescuing the aborted embryos to cross with other varieties. More recently, direct insertion of desired genes has been taking place.