What is the difference between positive and negative geotropism

Geotropism is a term called when it comes to occurrences pertaining to the growth of plants with respect to gravity. Gravity as a stimulus affects a plant’s growth, we can see this when the plant’s parts either grows upwards or downwards. There are two types of geotropism; this is called positive geotropism and negative geotropism. The difference between the two lies in the plants growth direction. In positive geotropism, the plant grows downwards while in negative geotropism, the plant grows upwards.  

Hunting in the darksome fish rely on senses beyond sight. in the darkness of the marianas trench, a fish called the rattail has an extremely sensitive sense of smell. the fish uses scent, rather than sight, to steer toward food. once it's near food, the rattail uses a special organ on the bottom of its chin to guide itself by feel.marine snowone staple of the deep sea diet is "marine snow," flakes of organic, edible substances that sink down from the upper ocean. animals at the ocean's bottom find sustenance in everything from the bodies of dead creatures to fecal matter. marine snow is diverse enough to support numerous species. for instance, several species of snails and worms feed exclusively on deceased whales.microorganismsthe deep sea is an intricate ecosystem, and even the ocean floor itself plays a part. hydrothermal vents are cracks in the sea floor where erupting magma mixes with ocean water to produce plumes of hot, sulfur-rich chemicals. some microbes can use these chemicals for energy, sustaining their existence and that of the animals who depend on their roles in the deep sea food chain.