Answer is Tropical.
The climate of a region is determined temperature and precipitation. Actually the climate of Pennsylvania is humid Subtropical climate. It is characterized by high temperatures and evenly distributed precipitation throughout the year. The average temperature for the year is 55.9°F (13.3°C). The warmest month, on average is July and coolest month is January. The average amount of precipitation for the year is 41.5" (1054.1 mm). The month with the most precipitation on average is also July.
Answer: The study, by Dr. Tim Brodribb and Dr. Taylor Field of the University of Tasmania and University of Tennessee, used plant physiology to reveal how flowering plants, including crops, were able to dominate land by evolving more efficient hydraulics, or 'leaf plumbing', to increase rates of photosynthesis.
Explanation: The reason for the success of this evolutionary step is that under relatively low atmospheric C02 conditions, like those existing at present, water transport efficiency and photosynthetic performance are tightly linked. Therefore adaptations that increase water transport will enhance maximum photosynthesis, exerting substantial evolutionary leverage over competing species.
The evolution of dense leaf venation in flowering plants, around 140-100 million years ago, was an event with profound significance for the continued evolution of flowering plants. This step provided a 'cretaceous productivity stimulus package' which reverberated across the biosphere and led to these plants playing the fundamental role in the biological and atmospheric functions of the earth.
A,b I think should be the answer
The outer skeleton provides protection due to the fact that invertebrates do not have backbones