Excretory system and urinary system are both working to remove waste in the human body. but technically, urinary system is part of the excretory system. The excretory system includes the kidney organ which is the main and the most important organ of the urinary system, another part of the excretory systems are the large intestine and the lungs. on the other hand, urinary system aside from kidney includes ureters, urinary bladder and the urethra. when the human body produces waste products, both the excretory and the urinary work together to remove these waste products from the human body.
Answer:Wildebeest are considered keystone species because their presence has myriad effects on the ecosystem, unlike those of any other species. Wildebeest are the "lawnmowers" of the Serengeti grassland. They keep grass short which in turn reduces the frequency of fires.
The ability of water to hold more heat than land keeps the temperature on Earth on a moderate level.
