do you believe humans are responsible for global warning or do you believe this is part of a natural cycle of earth like periodic ice age?

Both people and earth's natural phenomena are the one who are responsible for global warming. People abuse the nature; they burn many things, the smoke from vehicles and factories or other air pollutions can cause Global warming through Greenhouse effect. This disaster is also a phenomena and it's effect of Earth rotation around the sub.

as in mitosis, dna replication occurs during interphase.   in meiosis, it occurs specifically in s phase of interphase 1.