The answer is "stormy weather patterns"

A cold front moves faster than a warm air mass. The warm humid air is pushed up and results in a short period of heavy rain and possibly violent thunderstorms.

A warm front moves slower than a cold air mass. The warm air raises steadily above the cooler air mass and causes gentle rain showers for longer periods of time.

An occluded front is a combination of two fronts that form when a cold front catches up and overtakes a warm front. The result is a mix of rain showers and thunderstorms.

A stationary front is the boundary between two air masses when neither is moving. Clear skies to partly cloudy skies may result, with occasional light rain.

The answer is "high winds" because isobars represent changes in air pressure, and wind is caused by differences in air pressure.

A front is a boundary between two air masses.

Cold fronts are designated by lines of blue triangles.

Warm fronts are designated by lines of red semi circles.

A stationary front has both of a cold and warm front on the same line facing opposite directions. An occluded front has both a warm and cold front traveling in the same direction.

On weather maps, high pressure systems have an “H” at the center. High pressure systems bring cold air and spin outward.

Low pressure systems are marked with an “L.” They spin inward and bring warm air.

The answer is "tropical"

Tropical: In this hot and humid zone, the average temperatures are greater than 64°F (18°C) year-round and there is more than 59 inches of precipitation each year.
Dry: These climate zones are so dry because moisture is rapidly evaporated from the air and there is very little precipitation.
Temperate: In this zone, there are typically warm and humid summers with thunderstorms and mild winters.
Continental: These regions have warm to cool summers and very cold winters. In the winter, this zone can experience snowstorms, strong winds, and very cold temperatures—sometimes falling below -22°F (-30°C)!
Polar: In the polar climate zones, it’s extremely cold. Even in summer, the temperatures here never go higher than 50°F (10°C)!

The answer is "a cold front."

A front is a boundary between two air masses.
Cold fronts are designated by lines of blue triangles.
Warm fronts are designated by lines of red semi circles.
A stationary front has both of a cold and warm front on the same line facing opposite directions. An occluded front has both a warm and cold front traveling in the same direction.

On weather maps, high pressure systems have an “H” at the center. High pressure systems bring cold air and spin outward.
Low pressure systems are marked with an “L.” They spin inward and bring warm air.

The answer is "tornadoes, hail, high winds."

A front represents a boundary between two different air masses, such as warm and cold air. If cold air is advancing into warm air, a cold front is present. On the other hand, if a cold air mass is retreating and warm air is advancing, a warm front exists.

Thunderstorms are caused by moisture and differences in air pressure. Remember that warm air rises and cold air sinks. When warm, moist air is near the ground and cold, dry air is up above, convection will create unstable air currents where high pressure and low pressure systems meet. In a big thunderstorm cloud, there are now strong upward winds and downward winds happening at the same time. These are called updrafts and downdrafts. This is the most dangerous stage of the storm, when tornadoes, hail, winds and flooding can happen. Updrafts continue to fuel the storm with warm, moist air. But, once a storm runs out of updrafts, it starts to weaken.

The answer is "tornadoes, hail, high winds."

A front represents a boundary between two different air masses, such as warm and cold air. If cold air is advancing into warm air, a cold front is present. On the other hand, if a cold air mass is retreating and warm air is advancing, a warm front exists.

Thunderstorms are caused by moisture and differences in air pressure. Remember that warm air rises and cold air sinks. When warm, moist air is near the ground and cold, dry air is up above, convection will create unstable air currents where high pressure and low pressure systems meet. In a big thunderstorm cloud, there are now strong upward winds and downward winds happening at the same time. These are called updrafts and downdrafts. This is the most dangerous stage of the storm, when tornadoes, hail, winds and flooding can happen. Updrafts continue to fuel the storm with warm, moist air. But, once a storm runs out of updrafts, it starts to weaken.

The answer is "They cause warm air to rise and cold air to sink."
A front represents a boundary between two different air masses, such as warm and cold air. If cold air is advancing into warm air, a cold front is present. On the other hand, if a cold air mass is retreating and warm air is advancing, a warm front exists.

Thunderstorms are caused by moisture and differences in air pressure. Remember that warm air rises and cold air sinks. When warm, moist air is near the ground and cold, dry air is up above, convection will create unstable air currents where high pressure and low pressure systems meet. In a big thunderstorm cloud, there are now strong upward winds and downward winds happening at the same time. These are called updrafts and downdrafts. This is the most dangerous stage of the storm, when tornadoes, hail, winds and flooding can happen. Updrafts continue to fuel the storm with warm, moist air. But, once a storm runs out of updrafts, it starts to weaken.

The answer is "stormy weather patterns"

A cold front moves faster than a warm air mass. The warm humid air is pushed up and results in a short period of heavy rain and possibly violent thunderstorms.

A warm front moves slower than a cold air mass. The warm air raises steadily above the cooler air mass and causes gentle rain showers for longer periods of time.

An occluded front is a combination of two fronts that form when a cold front catches up and overtakes a warm front. The result is a mix of rain showers and thunderstorms.

A stationary front is the boundary between two air masses when neither is moving. Clear skies to partly cloudy skies may result, with occasional light rain.

Humans impact the physical environment in many ways: overpopulation, pollution, burning fossil fuels, and deforestation. Most notably, human impacts have contributed to climate change. Scientists attribute the global warming trend observed since the mid-20th century to the human expansion of the "greenhouse effect" — warming that results when the atmosphere traps heat radiating from Earth toward space. Certain gases in the atmosphere block heat from escaping. Gases that contribute to the greenhouse effect include: Water vapor, carbon dioxide, methane, nitrous oxide, and chlorofluorocarbons (CFCs). The effects of this are difficult to predict but some effects are more certain:

-On average, Earth will become warmer. Some regions may welcome warmer temperatures, but others may not.
-Warmer conditions will probably lead to more evaporation and precipitation overall, but individual regions will vary, some becoming wetter and others dryer.
-A stronger greenhouse effect will warm the oceans and partially melt glaciers and other ice, increasing sea level. Ocean water also will expand if it warms, contributing further to sea level rise.
-Meanwhile, some crops and other plants may respond favorably to increased atmospheric CO2, growing more vigorously and using water more efficiently. At the same time, higher temperatures and shifting climate patterns may change the areas where crops grow best and affect the makeup of natural plant communities.

Not all human impacts are negative. Ways in which people positively affect ecosystems around the world include:
-Recycling
-Establishing wildlife preserves and parks
-Creating green, open space laws
-Doing reforestation
-Creating environmental regulations

The answer is "restricting irrigation."

Humans impact the physical environment in many ways: overpopulation, pollution, burning fossil fuels, and deforestation. Most notably, human impacts have contributed to climate change. Scientists attribute the global warming trend observed since the mid-20th century to the human expansion of the "greenhouse effect" — warming that results when the atmosphere traps heat radiating from Earth toward space. Certain gases in the atmosphere block heat from escaping. Gases that contribute to the greenhouse effect include: Water vapor, carbon dioxide, methane, nitrous oxide, and chlorofluorocarbons (CFCs). The effects of this are difficult to predict but some effects are more certain:

-On average, Earth will become warmer. Some regions may welcome warmer temperatures, but others may not.
-Warmer conditions will probably lead to more evaporation and precipitation overall, but individual regions will vary, some becoming wetter and others dryer.
-A stronger greenhouse effect will warm the oceans and partially melt glaciers and other ice, increasing sea level. Ocean water also will expand if it warms, contributing further to sea level rise.
-Meanwhile, some crops and other plants may respond favorably to increased atmospheric CO2, growing more vigorously and using water more efficiently. At the same time, higher temperatures and shifting climate patterns may change the areas where crops grow best and affect the makeup of natural plant communities.

Not all human impacts are negative. Ways in which people positively affect ecosystems around the world include:
-Recycling
-Establishing wildlife preserves and parks
-Creating green, open space laws
-Doing reforestation
-Creating environmental regulations