The correct answer is C. The temperature of the water
Explanation:
In an experiment such as the one described about the speed of snails in water, the manipulated variable is the factor or element that is manipulated on purpose. This means the researcher or researchers slightly change this element to compare how this affects another variable. In this context, the manipulated variable is the temperature of the water because researchers used three different temperatures (cool, room-temperature, and warm), and therefore they manipulated or changed this factor. Moreover, it is expected temperature affects the distance nails move, which is the main variable.
Cyanobacteria, also known as blue-green algae, are found in vast quantities in fresh and salt water. Cyanobacteria are able to conduct photosynthesis. By utilising energy from the sun, they produce carbohydrates from water and carbon dioxide. As a byproduct, they produce oxygen. So cyanobacteria provided oxygen to the atmosphere that allowed other lifeforms to develop.
The first step of cellular respiration is glycolysis, where a six carbon glucose is broken down into a three carbon, this is called pyruvic acid. You're welcome
If you want the other steps in cellular respiration or cytology, just ask, I'm an A+.
