Carol and sam were using the microscope in science class. they used a dropper to put some pond water on their microscope slide. this is what they saw. "that is something living," said sam. "i don't think so," said carol. what do you think? explain.
a) this is not alive. it is not moving or responding.
b) this sample is made of identical units. it is not alive.
c) this is a multicellular organism made of cells. it is living.
d) this may have been alive once but not now because it is not moving.

For a research project, a student decided to test the effect of the lead(ii) ion (pb2+) on the ability of salmon eggs to hatch. this ion was obtainable from the water‐soluble salt, lead(ii) nitrate, which the student decided to make by the following reaction. pbo(s) + 2 hno3(aq) → pb(no3)2(aq) + h2o losses of product for various reasons were expected, and a yield of 86.0% was expected. in order to have 5.00 g of product at this yield, how many grams of pbo should be reacted? (assume that sufficient nitric acid, hno3, would be used.)