Answer:
a. To accommodate the population explosion, the city grew upward.
d. Frederick Law Olmsted designed a beautiful, formal park like those seen in most European capitals.
Step-by-step explanation:
Because of its over population, New York had to grow upward, there was no mor land available to build, so the only choice left was to start usin air space. Frederick Law Olmsted designed central park based on inspiration on Engladn, China and France where parks were public and all social classes had equal access to them.