input: Write a python function to scrape and save article titles and descriptions from a given URL into a CSV file.
  assert scrape_and_save('https://example.com/') == [['Example Title 1', 'Example Description 1'], ['Example Title 2', 'Example Description 2']]
  assert scrape_and_save('https://example.org/') == [['Example Title A', 'Example Description A'], ['Example Title B', 'Example Description B']]
output: def scrape_and_save(url):
      import requests
      from bs4 import BeautifulSoup
      import csv
      
      response = requests.get(url)
      soup = BeautifulSoup(response.content, 'html.parser')
      
      articles = []
      
      # Assuming the titles and descriptions are in <h2> and <p> tags respectively
      titles = soup.find_all('h2')
      descriptions = soup.find_all('p')
      
      for title, description in zip(titles, descriptions):
          articles.append([title.get_text(), description.get_text()])
      
      with open('articles.csv', 'w', newline='') as csvfile:
          writer = csv.writer(csvfile)
          writer.writerow(['Title', 'Description'])
          writer.writerows(articles)
      
      return articles