51.   But living organisms only use the left-handed versions.

52.   But the ongoing flowering of new American operas suggests that a medium long derided for pompous irrelevancy is, in fact, very much a living organism.

53.   But they had been bedeviled by how to apply the X-ray technique to the far more complex three-dimensional molecules, like proteins, that make up living organisms.

54.   But they have no information about how it might work in a living organism.

55.   But they also come from the decomposition and fossilization of living organisms.

56.   Carbonaceous chondrites are unusually rich in water and carbon compounds, the atomic building blocks of living organisms.

57.   Curiosity is an inborn characteristic in many living organisms, including human beings.

58.   DNA are the coiled molecules that decide whether a living organism becomes a person or a petunia, a possum or a peanut.

59.   Europa, the ice-crusted moon of Jupiter, is considered a possible habitat for living organisms in an ocean lying beneath the ice.

60.   Finding limestone on Mars could indirectly point to the past existence of bodies of water that might have spawned living organisms.