If a drought occurred how would you be able to tell from a trees rings

Identify the various levels of atmosphere. troposphere mesosphere exosphere stratosphere thermosphere

Recombinant dna is the merging of dna from unrelated organisms to create new genetic varieties is assembled in the lab from mononucleotides was part of the green revolution of the 1960s is pollination of one plant by another of the same species is cross-pollination of one plant by a different species

Everything in the universe originated from a single point. how was it possible for everything in the universe to have occupied a single point in space?