Answer:
Explanation: The United States of America and Canada have one of the worlds oldest environmental partnerships. The various ways they're partnering to better the environment include:
1. The U.S. - Canada Air Quality Agreement.
This Agreement was signed in 1991 with the aim of working towards the reduction of air emissions which cause cause acid rain. The Agreement was later expanded in the year 2000 with the goal of reducing transboundary smog emissions under the Ozone Annex.
2. The Great Lakes Water Quality Agreement.
This Agreement was initially signed in 1972, and amended in 2012. The goal of the Agreement is to provide a mechanism that involves the effort and cooperation of both countries, that will be geared toward the protection of the Great Lakes Basin ecosystem.
Answer: 
Explanation:
We have a right triangle with sides AB, BC=5cm and AC=13cm (the hypotenuse). Let's apply the Pithagorean Theorem to find AB:
(1)
(2)
(3)
(4)
Now that we know the value of each side of the triangle, we will use the trigonometric function sine to find the angles C and A (angle B is 
remembering we are talking about a right triangle):
For angle C:
(5)
(6)
(7)
For angle A:
(8)
(9)
(10)
Calculating the difference between both angles:
Answer:
Explanation:
Khyber Pass, Khyber also spelled Khaybar, orKhaibar, most northerly and important of the passes between Afghanistan and Pakistan. The pass connects Kābul with Peshāwar. The pass has historically been the gateway for invasions of the Indian subcontinent from the northwest. The name Khyber is also applied to the range of arid, broken hills through which the pass runs and which form the last spurs of the Spin Ghar (Safīd Kūh) Range. On either side of the connecting ridge are the sources of two small streams, the beds of which form the Khyber gorge. This narrow gorge forms the Khyber Pass; it winds between cliffs of shale and limestone, 600–1,000 feet (180–300 m) high, and enters the Khyber Hills from the Shadi Bagiār opening, a few miles beyond Jamrūd, Pak., and continues northwestward for about 33 miles (53 km). Just beyond the old Afghan fort of Haft Chāh, it opens onto the barren Lowyah Dakkah plain, which stretches to the Kābul River.
The Northwest Passage is a sea route that connects the Atlantic and Pacific Oceans through the Canadian Arctic Archipelago. In the past, the Northwest Passage has been virtually impassable because it was covered by thick, year-round sea ice.
Most likely due to the movement of plate tectonics. They are plates of earth under the ocean that move occasionally, over the years this is probably what happened. Plate tectonics are also the cause of most earthquakes and even tsunamis. Erosion could also play a factor in this as well.
