What is the role of dna helicase in the replication of dna?

Are characterized by dry conditions, limited vegetation and wide temperature range. a.) tropical rain forests b.) deserts c.) grasslands d.) none of the above

Is there any species that went extinct in recent years due to natural causes (not caused by human interaction). if so, what caused it?

According the inverse square law, doubling the distance from the source of the sound, a speaker, for example, will drop the sound 6 db each time. if you were standing in the back of an auditorium, 32 feet away from a speaker not using any amplification, would you be able to hear a speaker clearly? why or why not?