Why do birds fly? and also how to get rid of scariness of birds?

What element is able to combine with itself and hydrogen to form large molecules ?

Which is the correct formula for photosynthesis

Ihave no idea how to solve these. plus there's another question that is 2) a 10 kilogram meteorite is collected in space and brought back to earth. it is composed of 1.25 kg of uranium-238 and 8.75 kg of lead-206. how many u-238 half lives have passed? what is the approximate age of the meteorite?