Properly identifying each species.
Accurately recording his findings.
Not interfering with ecosystem while studying the birds.
Answer:
b. How does food yield energy?
Explanation:
The main question is how energy is produced from food such as carbohydrates, fats and proteins etc. First the carbohydrate is converted into glucose molecule and then glucose is absorbed by the cell and is broken down in the mitochondria of the cell with the addition of oxygen and generate energy in the form of adenine tri phosphate. All the scientists wants to know that how a food is converted into energy.
A model of a globe is a physical model. The limits are that the solar system is too big to be seen all at once. From the Tennessee science textbook, "Many years ago, scientists thought that Earth was the center of the universe and the sky was a blanket that covered the planet. Later through the observation, it was discovered that the objects you see in the sky are the sun, the moon ,stars, and other planets. This new model explained the solar system differently.
When cells communicate by the signaling process, one cell produces a signaling molecule that must be received by the signal receptor on or in the responding cell. Signaling molecules are often called ligands, a general term for molecules that bind specifically to other molecules (such as receptors).