What was one of the most important steps in the evolution of early
living things?

the development of the enzyme Rubisco and evolution of oxygenic photosynthesis.

Explanation: One can pick many key steps in early evolution: the development of the first cells, oxygenic photosynthesis, endosymbiosis leading to eukaryote organisms.

One important step was the mutation to the enzyme ribulose bisphospate carboxylase oxygenase (Rubisco) which enabled oxygenic photosynthesis.

The cyanobacteria that had Rubisco changed the planet’s atmosphere by producing oxygen as a by-product of photosynthesis. They were the most successful organisms of the time and have continued as a successful and ubiquitous group of organisms for billions of years.

The production of oxygen changed the direction of evolution profoundly. Later endosymbiosis led to the evolution of plants, with cyanobacteria the ancestors of chloroplasts, making Rubisco one of the most common enzymes on the planet.

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.  

a) carbon, hydrogen

b) carbon, hydrogen, oxygen, nitrogen

c) carbon, hydrogen, oxygen, nitrogen, phosphorus

d) sugar

e) amino acid

f) nucleotide