Answer:
Food is necessary to digest because food we eat is made of macromolecules.
Explanation: Macromolecules such as carbohydrates, proteins and lipids which are made of many small molecules i. e. glucose, amino acid and fatty acid respectively. Our body absorb food in the form of glucose, amino acid and fatty acid so it is necessary that the food is broken down into these small molecules.
<span>The central nervous system
consists of the two major structures: the </span><span>brain <span>and </span></span>spinal cord. The brain is encased in the skull, and protected by the
cranium.[7]<span> <span>The spinal
cord is continuous with the brain and lies </span></span><span>caudally <span>to the
brain and is protected by the </span></span>vertebra. These are
connected by nerve to send signals. So a tract is not part of the central
nervous system.
Answer:
Dependent variable: number of apples
Explanation:
In an experiment, the independent variable is the variable that isn't modified by the other variables measured in the experiment. In the example above indicated, the independent variable is the fertilizer used in the experiment. On the other hand, the dependent variable is the variable tested or measured in the experiment, thereby this variable is 'dependent' of the independent variable.
Natural Selection? Because of the struggle for existence
