I believe it is A beacuse nucleotides come from the word nucleus.
An organism describes an individual. You are an organism. I am an organism. The mosquito that flies by your window is an organism. An organism is a single, living thing and can be an animal, a plant, or a fungus. Organisms grow and respond to their environment.
A population is the term we use to describe multiple individuals or organisms of a single species that live within a particular geographic area. For example, there may be one population of painted turtles in one state and another population of painted turtles 250 miles away in another state.
The seeds she planted in the mud grew quicker because the mud is holding nutrition for the corn. The soil is a good guess to make, but the mud is more dense and moist. The water wouldn't have had more nutrients than the mud, just because the mud holds breakdown matter and other things from other plants.
There cannot be more carnivores than herbivores because the carnivores eat the herbivores. If there wasn't enough herbivores to eat, then the carnivores would eventually become extinct.