th saliva; as its teeth are weak and are not useful in catching agile prey. However, these teeth help in grinding the food that has been ingested before it is swallowed. The salivary glands help to produce saliva which is used to convert starch into sugar “and adds liquid to the ingested food” (TutorVista, n.d.). This food (which is mixed with the saliva) moves from the mouth to the pharynx and then it moves into the oesophagus. This food is then pushed further into “sac-like structure stomach” and is known as swallowing or “deglutition.” This food then mixes in with the enzymes and other fluids that are contained in the stomach, which occurs from the contraction of smooth muscles in the stomach. These food particles are propelled into the digestive tract – it is topped from moving back into the stomach through the sphincter valve. The now partially digested food then moves into the small intestine, this is where most of the digestion will occur. To help with the completion of digestion, juice from the pancreas and bile are secreted through the gall bladder (from the liver) to the small intestine. The small intestine absorbs the digestive nutrients – that are in the digestive system. However, the large intestine absorbs the unabsorbed nutrients and also reabsorbs water. Solids ate moved to the cloaca, while the liquid wastes are passed into the urinary bladder. Both the liquid and solid waste form the cane toad are “expelled” through the cloaca (“a slit that opens out finally in digestive system” – Tutor Vista, n.d.) Gas Exchange Structures and Mechanisms Earthworms do not have specialised respiratory organs like we do; instead they take in oxygen through their skin. These worms use diffusion to allow oxygen and carbon dioxide to pass through their skin. However, for diffusion to occur, the worm must have moist skin, to help with this mucous and body fluid from the excretory pores are released to keep its skin moist. This is linked to one of the reasons that earthworms usually surface at night, as it is cooler and the evaporating potential of the air is low. Similarly, the earthworm will spend most of its time– if not all (apart from certain night) – in the soil as this prevents their skin from drying out. The worms epidural layer has blood capillaries which are looped out from the vascular system circulating the blood. The gases can diffuse from the surrounding into and out of the blood through the skin and the capillary walls as the blood capillaries are so close to the skin. The gases circula>