What is the biggest difference between the geocentric model and the heliocentric model

Over time the trees in african have increased in length. many species have had to adapt to this change in order to survive. which of the following is a structural adaptation that has the african giraffe meet this change? question options: the african giraffe has become a faster at running from its predators. the african giraffe's neck has increased in size over the years. the african giraffe have moved to another part of africa. the african giraffe has not adapted and struggles to survive.

Sara goes on a slingshot ride in an amusement park. she is strapped into a spherical ball that has a radius 3*10^2 of centimeters. what is the volume of air in the spherical ball? use this formula: volume of a sphere=4/3pi,r^3 , where r is the sphere’s radius.

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?