sentences:  Often referred to as "microgravity", the lack of sedimentation, buoyancy, or convective flows in fluids results in a more quiescent cellular and intercellular environment primarily driven by chemical gradients.Certain functions of organisms are mediated by gravity, such as gravitropism in plant roots and negative gravitropism in plant stems, and without this stimulus growth patterns of organisms onboard spacecraft often diverge from their terrestrial counterparts.Additionally, metabolic energy normally expended in overcoming the force of gravity remains available for other functions.