Darwin hypothesized that new species could appear gradually through small changes in an ancestral species. What experiment did he conduct to test this hypothesis?
the breeding of finches
the breeding of pigeons
the observation of humans
the observation of dog breeds

before, trains worked using the steam engine. thus, it uses heat so it is crucial to apply heat balance. the steam engine absorbs energy during the stage of boiling water. so, this is the endothermic reaction. when the steam is used to work the piston, it has to release this energy through running the train. the excess energy is released as an exhaust to the chimney. this is the exothermic process because it releases energy to the surroundings.

1. is geographic distribution

2 is increasing complexity

3 is transitional forms