Your hypothesis is incorrect considering every day has the same length to it.
Answer:
The half of the Moon that points toward the Sun looks bright because it is lit by sunlight. The Moon appears to change shape because we see different amounts of the lit part as the Moon orbits Earth. ... As it moves around Earth, more and more of the lit side comes into view.
The respiratory system regulates oxygen flow, and provides regulation for oxygen blood content. Circulatory system plays a roll in providing enough oxygenated blood to the body
Answer:
Classification system changes because the scientists find new evidence in their studies.
Explanation: The world is always changing and growing and dying as well as developing, so over time things change. For example, as you grow up do you stay the same? No, you notice the physical changes happening, well thats sort of like how the earth and its ways are always changing as well.