In which organelle does photosynthesis take place? a. nucleus b. endoplasmic reticulum c. mitochondrion d. chloroplast

Select three sports that require participants to be highly fit before the beginning a: snowboarding b: skydiving c: rock climbing d: bungee jumping e: free diving f: hiking

Compare the composition of the moon's surface with the composition of the earth's surface.

Is becoming less expensive to screen blood samples for dna certain diseases have genetic basis what is possible ethical concern about the availability of inexpensive dna testing