Photosynthesis and cellular respiration are both complementary and relatively balanced on modern Earth, but early history of life on Earth showed increasing oxygen concentrations 2.5-2 billion years ago. This indicates that

d. the amount of photosynthesis occurring exceeded the amount of cellular respiration.

Explanation:

In the process of photosynthesis, oxygen is produced from carbon dioxide as plants make their own food. In cellular respiration, carbon dioxide is formed as oxygen is used to covert sugar into energy.

Photosynthesis produces oxygen and respiration produces carbon dioxide. If oxygen concentrations are increasing therefore, it means that more oxygen is being produced than being used which means that the amount of photosynthesis occurring must be higher than respiration because it is producing more oxygen than respiration can use.

d. stage 4

explanation:

the existence of some kind of demographic transition is widely accepted in the social sciences because of the well-established historical correlation linking dropping fertility to social and economic development.[1] scholars debate whether industrialization and higher incomes lead to lower population, or whether lower populations lead to industrialization and higher incomes. scholars also debate to what extent various proposed and sometimes inter-related factors such as higher per capita income,lower mortality, old-age security, and rise of demand for human capital are involved.[2]

heat released by collision processes during accretion, and heat from decay of radioactive elements

explanation: