1. What is a semipermeable membrane? 2. Make a list of molecules that enters the cell by diffusion and another list for molecules that get out of the cell by the same diffusion process.
3. (Reflexive questions) Name 2 life process that needs diffusion to occurs. Explain it.

The activity of the modern sample is 1.10 bq . how long does that measurement take?

Which is not a characteristic of bacteria? a. they are unicellular. b. they are prokaryotic. c. they are the smallest form of life on earth. d. they are multicellular.

For the strategies below, decide whether they are best described as demand-side solutions or supply-side solutions to meeting human needs for fresh water. remember that a demand-side solution reduces demand for fresh water, whereas a supply-side solution increases the supply of fresh water. (a) damming a river to create a reservoir (b) desalinating seawater (c) a nation invading a neighboring country to access their rivers (d) raising water prices for consumers and businesses (e) providing tax breaks for companies that use less water (f) replacing inefficient irrigation with more-efficient drip irrigation to grow crops (g) requiring low-flow showerheads in all new homes