The variables in a study of a cause-and-effect relationship are called the independent and dependent variables. The independent variable is the cause. Its value is independent of other variables in your study. The dependent variable is the effect.
A tissue.
Then a group of tissues that work together is an organ.
The a group of organs is an organ system.
A group of organ systems is and organism.
<h3>Answer:</h3>
According to Charles Darwin's theory of evolution by natural selection, organisms that possess heritable traits that enable them to better adapt to their environment compared with other members of their species will be more likely to survive, reproduce, and pass more of their genes on to the next generation. So, with a process called <em>Natural</em><em> </em><em>Selec</em><em>tion</em>, the species who adapts better to their environment survive for more time, until the environment change or until appear another species better to adapt than the first one
The most plausible hypothesis is: Tropical regions generally have more available water and higher levels of solar radiation. They also have very high rates of immigration and very low rates of extinction.
explanation:
Water is essential for an abundance of life, and sunlight is the means by which the whole food chain receives energy. Plants convert the sunlight into food, herbivores eat them, and other animals eat herbivores.
Hope this helps, and muchas luck on your biology.