Answer:
b. axons
Explanation:
The Peripheral Nervous System consists of nerves and ganglia. Nerves are nothing more than bundles of parallelly arranged nerve fibers surrounded by connective tissue. Each of these fibers is formed by an axon and the sheaths surrounding it. The ganglia, in turn, are accumulations of neurons, which usually form spherical structures, are located outside the central nervous system and are also linked by axons bridges.
The nitrogen in the air cannot be used by producers and consumers. It must be fixed or converted by bacteria in the ground into a useable form for plants called nitrates. Some plants called legumes (beans and clover) actually have bacteria in their roots.
The correct matches are:
- Atmosphere - Oxygen spilled into this sphere from ocean waters;
The majority of the oxygen in thee Precambrian Earth was not in the atmosphere, but instead it was in the ocean waters. With the emergence of life, large portions of this oxygen went into the atmosphere as it was released as a waste product.
- Biosphere - Cyanobacteria started to emerge as a life form;
The cyanobacteria were one of the earliest life forms. They were producers, and started to use the process of photosynthesis in order to produce food. The usage of this process caused lot of changes on the Earth later on.
- Hydrosphere - Oceans contained far less salt than they do today;
The rocks and minerals in the Precambrian Earth were not weathering and eroding in the manner they are now. Instead they were kept compact for much longer periods, influencing the mixture of of different components with the water as well in meantime.
- Lithosphere - Oxidation in rocks and minerals was not possible;
Because there was way to small amount of oxygen in the atmosphere, very close to 0%, the oxidation of rocks and minerals was not possible, as the oxygen is the gas that causes this process.
Natural selection is the process in which some organisms that show better adaptation to the environment are more likely to produce an offspring. In the case of the exercise, the answer is:
b. Some tuna live in the Pacific Ocean. They are fast, so they are likely to survive and pass on their genes.
It means that as they are better adapted to that environment due to the fact they are fast swimmers, they are likely not only to survive, but to pass their genes and produce offsprings.
