How did cyanobacteria affect earth's early atmosphere?
a.
they replaced oxygen with carbon dioxide in the atmosphere.
b.
they eliminated the harmful ultraviolet rays of the sun.
c.
they replaced carbon dioxide with oxygen in the atmosphere.
d.
they absorbed ozone molecules from the atmosphere.

The correct answer is option - C. They replaced carbon dioxide with oxygen in the atmosphere.

Explanation:

Cyanobacteria or Blue-green algae is a group of bacteria that is making its own food using water and carbon dioxide in the presence of sunlight, the process of photosynthesis

These organisms release oxygen as a byproduct of photosynthesis in the atmosphere. Through this process, these organisms replaced carbon dioxide with oxygen in the atmosphere in the early earth.

Thus, the correct answer is option C. They replaced carbon dioxide with oxygen in the atmosphere.

answer: decrease

a limiting factor is the one which decrease the abundance, distribution and causes extinction of the population of species in a ecosystem. here, predators including hawks, owls and snakes are the limiting factor for the population of mexican free tailed bat.   although bats are nocturnal animals as they forge for food at night these predators also may remain active during night which can decrease the population of the mexican free-tailed bats. also, these bats eat only one type of insects that are moths. the food can also be a limiting factor as all 400 members are dependent upon same type of food needs that are moths. the decrease in the moth population can cause decrease in population size of the mexican free-tailed bats.

therefore, the scenarios will most likely to decrease the population size of the mexican free-tailed bats.