Aplants rate of oxygen decreases , which change does this indicate ?
- the plants photosynthesis rate fell
- the plants energy demand rose
- the plants photosynthesis rate rose
- the plants energy demand fell

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.

geologic time scale (for gradpoint) =)

answer: dna

because all cells have genes

answerhomologous structures;