The WAPS (Water Across Plants) activity will investigate the plant growth under reduced gravity conditions, in particular the water movement across and out of the plant. It is planned to use the BIOLAB facility: BIOLAB supports biological experiments on micro-organisms, cells, tissue cultures, small plants and small invertebrates. Performing life science experiments in space identifies the role that weightlessness plays at all levels of an organism, from the effects on a single cell up to a complex organism including humans.