Question

[3] (3 points) Use what you know about the life-supporting properties of water to explain why we are searching for water on other planets as an indicator of life. [4] (3 points) Imagine that you are asked to design a randomized clinical trial to test the eftects o caffeinated coffee on brain activity. Briefly describe the experimental and control groups including how many participants you would include in each group. Identify two standardized variables in your experiment. [5] (3 points) How would you assess whether or not a possibly living organism from another planet were truly alive? [6] (3 points) Select an interesting thing you learned during our study of the chemistry of life. Write a question about your topic and then answer it

Answer 1

(3) The basic life supporting properties of water are as follows :

a) High specific heat: Water due to its high specific heat can absorb large amount of heat but with little change in temperature.This is the reason that water from water bodies like seas & oceans can absorb sun's radiation continuosly without boiling.Hence, the aquatic life are unaffected.

b) Density: Water has a very low density in solid state (i.e. ice) than in liquid state.Hence, ice floats on water surface insulating water bodies from cold which in turn allows aquatic life to thrive even in cold conditions.

c) Polarity: Water, being a polar molecule can form bonds with other polar molecules and work as an excellent solvent.

d) Hydrogen bonding: Such type of bonding allows water to dissolve other molecules and form intermolecular interactions with itself. This creates high surface tension needed for transportation of water in plants.

Due to these useful properties of water, it is searched on other planets as an indicator of life.