The answer would be B. Atom, star, galaxy, universe.
Explanation: atoms are small cells that make up everything in existence. They're too small to be seen by the naked human eye. Stars are big balls of gas that can be seen at night in the sky. These are second biggest because you can see these with the naked eye, but galaxies you can not. The galaxy holds the earth, all of the other planets, stars, and other things. If the galaxy can hold all of that then clearly it would be bigger than the stars. The universe is what holds our galaxy. There are millions of other galaxies out there in the universe. Ours is just a small one of an infinite number.
Answer: Cellular respiration is the process by which cells in plants and animals break down sugar and turn it into energy, which is then used to perform work at the cellular level.
Explanation: In simpler words, it provides energy for the cell to do basic needs.
Answer:
Answer is A. allow them to control all the variables involved.
Explanation:
Modelling in ecology means the use of constructed mathematical models for understanding of ecological processes and to predict or know how real it is for ecosystem to change.
Ecological modelling is useful in defining problems more precisely and clarity of concepts.
Scientific methods must be supported by observations and results from many investigations and are not absolute.