Do you believe humans are responsible for global warming or do you believe this is part of a natural cycle of Earth, like periodic ice ages? Use your research to support your opinion.

(! ) what’s fracking and what does it have to do with carbon, carbon dioxide, or fossil fuels?

How do the sperm cells get from the stigma to the ovules? a. they slide down the petals to the bottom of the flower. b. they travel through pollen tubes. c. they travel along filaments. d. insects carry the sperm cells from the stigma to the ovules.

20 the main source of energy for our planet comes from the