Desertification is caused by  A. human activity
B. leaching of the soil
C. solar heating patterns
D. temperature variations

Which element is used in photosynthesis found in atmosphere and fixed by bacteria?

The vaccine in a flu shot contains weakened flu viruses. how does a flu shot work with the immune system? a. it destroys lymphocytes. b. it destroys macrophages. c. it activates macrophages. d. it activates lymphocytes.

Toorale man murder mystery < - your lab link 1. how was the toorale man found? 2. what did archaeologists learn about the burial? why is the burial important? 3. what information were the scientists able to learn from the skeleton itself? 4. why is the question of whether the injuries came from a stone or steel weapon important? how could scientists distinguish between the different types of weapons? 5. what did the carbon dating and soil testing tell scientists about toorale man? why are the dates interesting for scientists?