Which of the following are changes to the environment which can lead to the spread of infectious diseases?
1.) soil erosion
2.) habitat destruction
3.) creation of irrigation canals and dams
4.) all of the above

Most animal cells membranes have proteins that pump ions out of the cell and potassium ions into the cell

What happens when water’s salinity increases? mass decreases. freezing point decreases. buoyancy of objects decreases. the amount of dissolved minerals decreases.

Many organizations release indexes used to measure the development of the world's countries. as we learned in this lesson, these indexes measure many factors, from life expectancy to happiness. in your opinion, what are the three most important factors we can use to determine how developed a country might be? explain your answers in a few sentences.