How long ago do we think cells with nuclei developed on earth?

Creating new things to solve problems and improve life depends on the close interaction of which two fields?

Fossils of ancestors of the modern horses show a small 4-toed almost dog-like browsing animal named eohippus over time the horses got larger lost toes and changed to a grazing diet what is the best explanation of why this change occurred

Cloning an individual usually produces orangisms that (1) contain dangerous mutations (2) contain identical genes (3) are identical in appearance and behavior (4) produce enzymes different from the parent