If photosynthesis produces cellular energy (atp) from sunlight, why do plant cells also need to perform cellular respiration, a process that produces atp from sugar

What element is able to combine with itself and hydrogen to form large molecules ?

The activity of the modern sample is 1.10 bq . how long does that measurement take?

The picture shows a location in india that is very dry and arid. notice the tall mountains in the background; you can find high amounts of vegetation on the other side of the mountains. which statement is most likely true for this area?