Which factors add to the greenhouse effect and are caused by human activities? Select two options.

a decrease in the amount of dust in the atmosphere
a decrease in the amount of water on Earth’s surface
an increase in gases in the atmosphere that absorb heat
an increase in surfaces that radiate energy into the atmosphere
an increase in the amount of solar radiation that reflects into space

Look at the spectrums of a star moving towards earth and a motionless star. which of these is a correct inference that can be draw from the observation of the two spectrums? (2 points) the spectrum of a motionless star is difficult to be viewed separately using oridinary telescopes. the spectrum of a motionless star is identical to the spectrum of a star which moves towards earth. the spectrum of a star shifts towards the red region when the star moves towards earth. the spectrum of a star shifts towards the blue region when the star moves towards earth.

7. in the cycle, a virus integrates its dna into the host's dna, and its dna is replicated when the host dna is replicated. a. infectious b. retroviral c. lysogenic d.lytic

How do you know when a chemical reaction has occurred