కింది పదాలకు వ్యతిరేక పదాలను రాయండి. ఆ పదాలతో వాక్యాలు రాయండి.
అవమానం
మర్యాద..
దురదృష్టo
adhairyam
Answers
Explanation:
Certain plants have adapted so they can withstand long periods without water. Yuccas, for instance, have deep root systems that can seek out water with incredible efficiency. Cacti have spiny, hairy spines, spikes, or leaves that limit how much water they lose to evaporation. Mosses can withstand complete dehydration. Juniper trees can self-prune by steering water only toward the branches required for survival. Other plants only grow when there is enough water to support them. In periods of drought, their seeds can survive under the soil for years until conditions are favorable again.
However, many organisms cannot adapt to drought conditions, and the environmental effects of extended, unusual periods of low precipitation can be severe. Negative impacts include damage to habitats, loss of biodiversity, soil erosion, and an increased risk from wildfires. During the U.S. drought of 1988, rainfall in many states was 50 to 85 percent below normal. Summer thunderstorms produced lightning without rain and ignited fires in dry trees. In Yellowstone National Park 36 percent of the park was destroyed by fire.
Drought can also create significant economic and social problems. The lack of rain can result in crop loss, a decrease in land prices, and unemployment due to declines in production. As water levels in rivers and lakes fall, water-supply problems can develop. These can bring about other social problems. Many of these problems are health-related, such as lack of water, poor nutrition, and famine. Other problems include conflicts over water usage and food, and forced migration away from drought-stricken areas.
While drought is a naturally occurring part of the weather cycle and cannot be prevented, human activity can influence the effects that drought has on a region. Many modern agricultural practices may make land more vulnerable to drought. While new irrigation techniques have increased the amount of land that can be used for farming, they have also increased farmers’ dependence on water.
Traditional agricultural techniques allow land to “rest” by rotating crops each season and alternating areas where livestock graze. Now, with many areas in the world struggling with overpopulation and a shortage of farmland, there is often not enough arable land to support sustainable practices. Over-farming and overgrazing can lead to soil being compacted and unable to hold water. As the soil becomes drier, it is vulnerable to erosion. This process can lead to fertile land becoming desert-like, a process known as desertification. The desertification of the Sahel in North Africa is partly blamed on a prolonged drought whose effects were intensified by farming practices that result in overgrazing.
Increased drought conditions in Kenya have been attributed to deforestation and other human activities. Trees help bring precipitation into the ground and prevent soil erosion. But in 2009, it was reported that one-quarter of a protected forest reserve had been cleared for farming and logging, leading to drought conditions affecting 10 million people around the country.
Historical Droughts
Scientists often study historical droughts to put modern-day droughts in perspective. Since our data from thermometers and rain gauges only goes back about 100 to 150 years, scientists must research paleoclimatology, the study of the atmosphere of prehistoric Earth. Scientists gather paleoclimatic data from tree rings, sediments found in lakes and oceans, ice cores, and archaeological features and artifacts. This allows scientists to extend their understanding of weather patterns for millions of years in the past.
Analyzing paleoclimatic data shows that severe and extended droughts are an inevitable part of natural climate cycles. North America has experienced a number of long-lasting droughts with significant effects. It is thought that droughts brought about the decline of the Ancestral Puebloans in the Southwest during the 13th century, and the central and Lower Mississippian societies in the 14th to 16th centuries.
In South America, massive migration out of the once-fertile Atacama Desert 9,500 years ago can be explained by the onset of extreme drought.