Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the best answer to each of the following questions from 23 to 30.

Urban green spaces, such as parks and gardens, provide numerous benefits to city residents. These spaces offer a retreat from the bustling city environment, allowing people to relax, exercise, and socialize. Research has shown that spending time in green spaces can reduce stress and improve mental well-being. For children, these areas provide a place to play and interact with nature, which is essential for their development.

Green spaces are not only beneficial to people but also contribute to the environment. Trees and plants absorb carbon dioxide and release oxygen, which improves air quality. Additionally, green areas can help control urban temperatures by providing shade and reducing the heat island effect, where cities become significantly warmer than surrounding areas. This cooling effect is especially important as global temperatures continue to rise.

Local governments around the world are recognizing the importance of urban green spaces and are taking steps to create more of them. Initiatives include turning vacant lots into community gardens, building rooftop gardens, and even designing "green buildings" with plants integrated into their structure. These aim to make cities more sustainable and livable for future generations.

Despite the clear advantages, green spaces face challenges such as limited land availability and funding issues. In densely populated cities, finding space for new parks can be difficult. However, innovative approaches, like vertical gardens and green roofs, offer potential solutions to maximize greenery in urban areas, even in small spaces.

The word "vertical" in paragraph 4 is OPPOSITE in meaning to _______.