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

Got Climate Anxiety? These People Are Doing Something About It

     Distress over global warming is increasing, but formal and informal support networks are springing up, too. After Britt Wray married in 2017, she and her husband began discussing whether or not they were going to have children. The conversation quickly turned to climate change and to the planet those children might inherit. She said she became sad and stressed, crying when she read new climate reports or heard activists speak. Jennifer Atkinson, an associate professor of environmental humanities at the University of Washington, Bothell, became depressed after students told her they couldn't sleep because they feared social collapse or mass extinction. 

     There are different terms for what the two women experienced, including eco-anxiety and climate grief, and Dr. Wray calls it eco-distress. It's also not unusual. Over the past five years, according to researchers at Yale University and George Mason University, the number of Americans who are very worried” about climate change has more than doubled, to 26 percent. In 2020, an American Psychiatric Association poll found that more than half of Americans are concerned about climate change's effect on their mental health. 

     But as the prevalence of climate anxiety has grown, so has the number of people working to alleviate it, both for themselves and those around them. Dr. Wray, for example, who holds a Ph.D. in science communication, began reading everything she could about anxiety and climate change, eventually shifting her own research to focus on it entirely. She shares her findings and coping techniques in a weekly newsletter, Gen Dread, with more than 2,000 subscribers. In the spring of 2022, she plans to publish a book on the topic. “My overall goal is to help people feel less alone,” Dr. Wray said. "We need to restore ourselves so we don't burn out and know how to be in this crisis for the long haul that it is.” Dr. Atkinson, in hopes of assuaging her feelings and those of her students, designed a seminar on eco-grief and climate anxiety. 

          For many Americans, counseling for climate distress is relatively accessible. In some communities, however, especially in less wealthy countries, it may seem more like a rare privilege

What does the word "prevalence" in paragraph 3 mean?