Final answer:
There is no scientific evidence of Martian extraterrestrials to suggest an increase or decrease in their numbers. However, the human perception of alien life visiting Earth was believed by 36% of American adults in 2012. Human population growth is very rapid, possibly exponential, but the current growth rate is decreasing from past trends, and challenges related to space and resources are debated. None of the options.
Step-by-step explanation:
Regarding the number of Martian extraterrestrials, there is currently no scientific evidence to support the existence of life on Mars, thus no credible data on any changes in such a population. Now, if we look into human perspectives on extraterrestrial life, in a 2012 Kelton Research poll, it was found that 36% of adult Americans thought that alien beings have actually landed on Earth. With an adult population in the United States of about 222,000,000 in 2012, this belief would amount to approximately 79,920,000 adults, if we use scientific notation (2.22 x 10ΒΈ adults).
The rate of human population growth is experiencing a very rapid increase according to Max Roser's data visualization, which implies that the growth model could be considered exponential. However, recent trends suggest that growth rates are actually slowing down compared to past rates.
Overpopulation issues have been hotly debated, with concerns about available space and resource pressures due to the increasing human population, yet the full impact is complex and dependent on numerous factors, including technology, consumption patterns, and environmental sustainability practices. None of the options.