18. over time, how do sand dunes tend to migrate? a. perpendicular to the movement of the wind b. in the same direction as the wind blows c. toward the wind d. in random directions

in the same direction as the wind blows

Explanation:

The dunes are hills formed by grains of sand held together by the action of wind or water. Over time, as sand dunes tend to migrate in the same direction as the wind blows.

They have a larger side that is eroded (windward) and a smaller, steeper side (leeward) where deposition of eroded material occurs. Through this mechanism of erosion and deposition the dunes are considered highly dynamic, "moving" over time.

picture a world where computers are building made-to-order personalized robotic arms and synthetic organs, drones are circulating above mars! due to the rapid growth of technology, the future has never been more unpredictable, and it presents a huge challenge in education: we are teaching students how to work in a future that we have never been unsure of. it is widely predicted that in eight years’ time, there will be more jobs in the fields of science, mathematics, technology and engineering than in any other discipline. and, as the technology continues to develop, it will soon become clear that addressing social problems will involve more innovative thinking, and analytical and technical knowledge than ever before. undeniably, there are no subjects that encourage innovative and creative thinking, deep thought, problem solving and independence more than the stem subjects. while it is widely commented on that there is a need to reimagine the ways stem subjects are taught in schools by embracing a more interactive and innovative approach to appeal to more students, it should come as no surprise that some of the most reputable educational organizations in the world are already implementing changes to embrace stem. harvard, for example, announced in 2014 that they were increasing their computer science faculty by over 50% and has since introduced computer science as a core subject for all freshmen. the urgency of supporting stem subjects at a young age is becoming more relevant than ever, as adopting a keen interest in the curricula needs to happen early. however, beyond the age issue is one of gender.

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glacial erosion, the picking up and movement of earth beneath a glacier, is also referred to as plucking. erosion and transportation of individual pieces of bedrock, especially large "joint block occur as a result of this glacial erosion. plucking is type of erosion in which rocks become frozen into the bottom and sides of the glacier.as the glacier moves downhill it 'plucks' the rocks frozen into the glacier from the ground.