The correct answer to this question is this one: they lacked oxygen. The earliest organisms were completely heterotrophic in nature because of the reason that they lacked oxygen. <span>A heterotroph is an organism that cannot fix carbon and uses organic carbon for growth. </span>
Answer:
Likewise, competition for food among deep-water fish that eat the same types of food will .
Explanation:
Natural selection will condemn all deep-sea fish to the same environment that conditions them, those that cannot develop gills will be exposed to extinction, this refers to the theory of the evolution of the fittest by Charles Darwin.
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.
