Left-handedness is extremely common in twins. It is unusual, however, for both to be left-handed.
There are close to 4,000 known species of frogs, including toads. The biggest frog is the appropriately named Goliath frog (Conraua goliath) of Cameroon. They reach nearly 30cm (a foot) and weigh as much as 3.3 kilograms. The smallest frog is the Gold frog (Psyllophryne Didactyla) of Brazil. They grow to only 9.8 mm (3/8 inch).
Only one-fifth of air is oxygen. Most of the rest is nitrogen.
Mount Everest is more than 29-thousand feet high, which makes it almost 50-percent taller than Mount McKinley.
Mount McKinley is taller than Africa’s Kilimanjaro or Japan’s Mount Fuji or any of the Alps. That should give you an idea how tall Everest really is.