What is the difference between ionic bond and covalent bond?

In terms of alternation of generations, the internal parts of the pollen grains of seed-producing plants are most similar to a ) moss sporophyteb) moss gametophyte bearing both male and female gametangiac) fern sporophyted) fern gametophyte bearing only antheridia

Why are common names a problem for scientist?

What does it mean for an allele to be dominant?