How does hydroelectric power plant convert energy

When a beta particle is emitted, the mass number of the nucleus a. decreases by one b. increases by one c. remains the same d. decreases by two

Ascientist wants to know how individual lions within a pride interact with each other in their own environment. to do this, the scientist sedates and tags all of the lions within a pride. then, he places several remotely-controlled video cameras near the lions' den and performs an observational field study. he collects continuous video footage over the span of one year, analyzes the video, and then forms conclusions based on his observations.

How much would the freezing point of water decrease if 4 mol of nacl were added to 1 kg of water (kf=1.86 degrees c/(mol/kg) for water and i=2 for nacl a- 7.44 degrees c b- 14.88 c 3.72 d 1.86