The answer should be rain water
Lying generally between the foot of acontinental rise and a mid-ocean ridge,abyssal plains cover more than 50% of the Earth's surface. the zone of theocean floor that separates the thinoceanic crust from thick continentalcrust. ... the slope between the outer edge of the continental shelf and thedeep ocean floor.
Answer:
An increase of 3,500 J
Explanation:
Given that,
Energy added by swimmer = 12000 J
Heat removed by the surrounding = 8500 J
We need to find the total change in energy. It can be calculated using the law of conservation of energy such as :

As the change in energy is positive, it means that there is an increase of 3500 J.