Which of the following is/are responsible for giving a galaxy its particular shape?

a. dark matter
b. supermassive black holes
c. dust and gas
d. cosmic microwave background radiation

Which of the following statements best describes what is occurring in the land surrounding the sahara desert? a desertification is increasing, and the desert is expanding. b. fewer people are trying to farm in this semiarid region. c. the desert is shrinking with the increased use of irrigation. d. increased urbanization has resulted in decreased deforestation. select the best answer from the choices provided mark this and return save and exit next submit