How different are dog and human brains?

What gases are present in lava? What happens when hot magma meets cold water in the sea? How different is an animal's brain to my own? How much of my intelligence is down to genes, and how much is the environment in which I grew up? Do photons weigh anything? Is there a cancer pandemic? And will a spoon in the neck of the bottle keep champagne fizzy? Dr Chris and Lester Kiewit tackle your burning questions...