What is the makeup of white blood cells in the human blood?

Iguanas need to live in a habitat that is very warm, so the pet store warms their enclosures with "basking lights" which act as an artificial sun. describe how the three methods of thermal energy transfer may take place within the iguana's enclosure.

This map shows how climate change might affect precipitation patterns in the great plains of the united states by the end of this century. brown shoes a decrease in percipitation, and blue shows an increase. the maps differ based on the predictive levels of green house emissions. the maps shows that northern area should get a. more pracipations regardless of emmissions b. less pracipation, regardless of emmissions levels c. more precipitation, but only when emission levels. southern areas show a. more pracipations regardless of emmissions b. less pracipation, regardless of emmissions levels c. more precipitation, but only when emission levels. to use these maps to prepare for natural disasters in the great plains, scientist need to ask? a. how many tons of emissions were used at the basis of the map. b. which types of fossil fuels are used in the great plains c. if you think the above is wrong it's probly c the question is cut off

In general, characteristics that an organism survive and reproduce become more common in a population over time. what mechanism of evolution cause this change?