What are causes of high temperatures inside Earth?

Select all that apply.

friction caused by Earth’s fast rotation
radioactivity due to heavy elements
heat trapped from when Earth formed
various fossil fuels burning slowly

What is the identity of the planets?

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?

Which of the following cell structures is significantly different between gram- positive and gram-negative bacteria?