2. What made scientists think that the change in Tibetans was caused by natural selection A. because the gene for adapting to high altitude is found in their Han relatives
B. because the gene for adapting to high altitude is NOT found in their Han relatives
C. because the gene for adapting to high altitude is NOT in both of them

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

The fruit of a certain plant is sweet and fleshy. the seeds of this plant have a seed coat that is fairly tough. the seeds germinate better if they are exposed to acid, or scarification. what is the most likely type of dispersal for this seed? water animal wind

In 2015, about ten percent of total u.s. energy consumption was from renewable energy sources. renewable energy plays an important role in reducing greenhouse gas emissions. when renewable energy sources are used, the demand for fossil fuels is reduced. sanjay and his family want to cut back on their use of non-renewable resources at home. they are thinking of an alternate way to heat their home without adding more greenhouse gases or pollutants to the environment. which renewable resource would not fit into their plan? a) solar power b) burning wood c) constructing a wind turbine eliminate d) generating hydroelectric power