A scientist is analyzing two different sounds, one from a deer and one from a zebra, with a device that allows her to see the sound waves of each noise. While looking at the results, she sees that the sound waves for the deer are more closely packed together, but the zebra's sound has very spread out waves. Which animal's sound has a lower pitch? Hint: Look at the police car in Figure below . The sound waves from its siren travel outward in all directions. Because the car is racing forward (toward the right), the sound waves get bunched up in front of the car and spread out behind it. As the car approaches the person on the right (position B), the sound waves get closer and closer together. In other words, they have a higher frequency. This makes the siren sound higher in pitch. After the car speeds by the person on the left (position A), the sound waves get more and more spread out, so they have a lower frequency. This makes the siren sound lower in pitch. A change in the frequency of sound waves, relative to a stationary listener, when the source of the sound waves is moving is called the Doppler effect . You've probably experienced the Doppler effect yourself. The next time a vehicle with a siren races by, listen for the change in pitch. For an online animation of the Doppler effect, go to the URL below.
Ans: zebra

In school, Jeremy's class has been assigned pen pals on the other side of the planet to write to. Jeremy lives in the United States and has been assigned to a girl named Marge who lives in Australia. Jeremy was told by his teacher that although Jeremy's town is in the winter season, Marge's country is currently experiencing summer. This idea intrigues Jeremy so in his first letter he is going to ask Marge many questions about this subject. Who will wear warmer clothes to school? Hint: The axial tilt of the Earth is approximately 23.439281 with the axis of its orbit plane, always pointing towards the Celestial Poles. Due to Earth's axial tilt, the amount of sunlight reaching any given point on the surface varies over the course of the year. This causes the seasonal change in climate, with summer in the Northern Hemisphere occurring when the Tropic of Cancer is facing the Sun, and winter taking place when the Tropic of Capricorn in the Southern Hemisphere faces the Sun. During the summer, the day lasts longer, and the Sun climbs higher in the sky. In winter, the climate becomes cooler and the days shorter. In northern temperate latitudes, the Sun rises north of true east during the summer solstice, and sets north of true west, reversing in the winter. The Sun rises south of true east in the summer for the southern temperate zone and sets south of true west.
Ans: Jeremy

Two neighboring farms both had depleted soils due to intensive agricultural practices for decades. Apple far decided to start an agroforestry system and other methods to protect their depleted soils, while Pear farm did nothing and had big losses the following years. Which farm didn't reduce the nutrient loss into streams? Hint: Depleted soils can be protected from soil erosion by groundcover plants such as naturally growing grasses in agroforestry systems. These help to stabilise the soil as they increase cover compared to short-cycle cropping systems. Soil cover is a crucial factor in preventing erosion. Cleaner water through reduced nutrient and soil surface runoff can be a further advantage of agroforestry. The runoff can be reduced by decreasing its velocity and increasing infiltration into the soil. Compared to row-cropped fields nutrient uptake can be higher and reduce nutrient loss into streams.Further advantages concerning plant growth:
Ans: Pear

Two villages were situated on different sides of the hill. Each village has its own approach to agriculture. East village decided to clear the land, by felling many trees and bushes, and set up a vast irrigation system. West village too a more natural approach to food production and applied the edible forest method, and all the permaculture principles over the years. Which village's soil had more mobilized salts? Hint: Groundwater salinization compromises buffering properties. Vegetation clearance, along with irrigation, causes serious issues. Irrigation increases the water table and mobilizes salts, and vegetation clearance allows it to come in contact with water habitats and vegetation. This stresses species not adapted to high salinity. High levels of salinity reduces water uptake in plants, by causing stomatal closure, reducing photosynthesis. Forests undergo decline in areas of high salinity and shallow groundwater depths because these conditions make them more susceptible to droughts. Forests undergo decline in areas of high salinity and shallow groundwater depths making them more susceptible to droughts.
Ans: East