Read the following passage and choose the letter A, B, C, or D to indicate the correct answer to each of the questions.

The desert, with its extreme weather conditions, is a difficult place for plants to grow and thrive. Plants release water inside them in the form of moisture or water vapor through the process of transpiration. However, as water is hard to get in deserts, many plants have adapted to save water in several different ways. They can control either the loss of water used during transpiration or the amount of water they can get and store. Succulents, such as cacti, store as much as they can hold in large storage areas in their roots, leaves, or stems, which gets them through the dry season. Annuals, plants that grow for part of a year, produce seeds that can tolerate the dry season while the adult plants can avoid the hot and dry conditions of the dry season. Plants growing in the desert have a few tricks to help them handle the harsh conditions. The numerous spines on cacti provide shade and reduce the evaporation of water. Some plants may grow very long roots of up to 100 feet in length to reach groundwater stored deep underground. For some plants, one way to get enough water is to remove the competition from nearby plants. For example, the creosote plant produces toxins that make it difficult for other plants to grow in the surrounding soil. This keeps away plants that can use up the plant’s water supply.

Choose the options that best complete the passage.In 2018, a study by the United Nations revealed th...