Government policies play a crucial role in mitigating climate change, but their effectiveness varies significantly depending on the policy type, political context, and national priorities. Examining the approaches of two countries – the European Union and China – reveals both successes and limitations.

European Union: The EU has implemented a comprehensive range of policies, including the Emissions Trading System (ETS), renewable energy targets, and energy efficiency regulations. The ETS, a cap-and-trade system, aims to reduce carbon emissions from power plants and industries. Renewable energy targets incentivize investment in solar, wind, and hydro power. Energy efficiency standards for buildings and appliances are also key components. Effectiveness: The ETS has had some success in reducing emissions, but its effectiveness has been hampered by carbon leakage (industries relocating to countries with less stringent regulations). Renewable energy targets have spurred significant growth in the renewable energy sector, but achieving the targets consistently remains a challenge. Political disagreements between member states have also slowed progress.

China: China is the world's largest emitter of greenhouse gases, but it has also made significant investments in renewable energy and energy efficiency. China has set ambitious targets for reducing carbon intensity and increasing the share of non-fossil fuels in its energy mix. Large-scale investments in solar and wind power are transforming the energy landscape. Policies promoting electric vehicle adoption and stricter emission standards for vehicles are also in place. Effectiveness: China's investments in renewable energy are impressive and are contributing to a reduction in carbon intensity. However, the country's continued reliance on coal for power generation remains a major obstacle. Policy implementation can be uneven, and enforcement of environmental regulations can be weak in some areas. The scale of the challenge is immense, and the effectiveness of current policies remains to be seen.

In conclusion, government policies have the potential to be highly effective in mitigating climate change, but their success depends on a combination of strong political will, comprehensive policy frameworks, and effective enforcement. The EU's experience highlights the challenges of international cooperation, while China's demonstrates the potential for large-scale action, albeit with ongoing challenges.

Answer: Drought poses a significant challenge to plant survival, leading to a variety of adaptations. These can be broadly categorised as physical and physiological. Physical adaptations involve structural features that reduce water loss or enhance water uptake. Examples include:

• Reduced leaf surface area: Small leaves, spines (e.g., cacti), or modified leaves (e.g., needles of conifers) reduce transpiration.
• Thick, waxy cuticle: This layer on the leaf surface limits water loss through evaporation.
• Sunken stomata: Stomata located in pits or depressions reduce air movement and transpiration.
• Underground storage organs: Roots, tubers, or bulbs store water for use during dry periods.

Physiological adaptations involve changes in the plant's internal processes. These include:

• CAM photosynthesis: Stomata open at night to take in CO2, reducing water loss during the day. CO2 is stored and used for photosynthesis during the day when stomata are closed.
• Drought tolerance: Ability to tolerate significant water loss without damaging cells. This often involves changes in cell membrane composition.
• Deep root systems: Access to groundwater sources.
• Reduced leaf number: Minimizes the total surface area exposed to the sun and wind.

The effectiveness of these adaptations varies depending on the environment. For example, CAM photosynthesis is highly effective in arid environments with high temperatures and low humidity. However, it can be slower than C3 photosynthesis. Plants with deep root systems are better suited to environments with access to groundwater. The effectiveness of physical adaptations like thick cuticles is also dependent on the intensity of sunlight and wind. In environments with frequent and intense sunlight, a thick cuticle is crucial. In areas with high winds, reduced leaf surface area is more beneficial.

Evaluation: While these adaptations enhance survival, they are not always foolproof. Extreme or prolonged droughts can overwhelm even the most well-adapted plants. Furthermore, some adaptations come at a cost, such as slower growth rates or reduced reproductive success. The interplay between adaptation and environmental conditions is complex and determines the success of plant species in drought-prone areas.

Plants in hot arid and semi-arid environments face significant challenges, primarily water scarcity and extreme temperatures. To survive, they have evolved a range of remarkable adaptations. These adaptations can be broadly categorized into those related to water conservation and those related to temperature regulation.

Water Conservation Adaptations:

• Reduced Leaf Surface Area: Many plants have small leaves, spines, or no leaves at all (e.g., cacti). This reduces the surface area exposed to the sun, minimizing transpiration.
• Thick, Waxy Cuticle: A thick, waxy cuticle on leaves and stems reduces water loss through evaporation.
• Succulence: Succulent plants (e.g., cacti, aloe) store water in their stems, leaves, or roots. This provides a reservoir of water during dry periods.
• Deep Roots: Some plants have very deep taproots that reach underground water sources. Others have shallow, widespread root systems to quickly absorb surface water after rainfall.
• Reduced Stomata: Stomata (pores for gas exchange) are often sunken or protected by hairs to reduce water loss. They may also be closed during the hottest part of the day.
• CAM Photosynthesis: Crassulacean Acid Metabolism (CAM) is a photosynthetic pathway where stomata open at night to take in CO2, reducing water loss during the day. CO2 is stored as an acid and then used for photosynthesis during the day when stomata are closed.

Temperature Regulation Adaptations:

• Light Colour: Light-coloured leaves and stems reflect sunlight, reducing heat absorption.
• Hairy Leaves: Hairs on leaves create a layer of insulation, reducing heat absorption and transpiration.
• Vertical Orientation: Some plants have a vertical orientation to minimize exposure to the intense midday sun.

Examples of plants exhibiting these adaptations include cacti (succulence, spines, CAM photosynthesis), xerophytic shrubs (reduced leaves, thick cuticle), and grasses with deep roots.