Questions

A biosphere is the sum of all the ecosystems established on planet Earth.

An ecosystem is an area in which the plants and animals all interact to create a living environment. Therefore ecosystem is a smaller unit of earth, all ecosystems together form the earth.

The branch of biology that studies the different structures and functions of the cell is called Cell Biology or Cytology.

 A cell is the smallest unit of life that can replicate independently, and cells are often called the "building blocks of life"

Cell Biology deals with :

• Life cycle 

• Structure and organisation of cell organelles and their physiological properties. 

• Metabolic processes 

• Interactions with their environment 

• Signalling pathways.

A scientific theory is a well-substantiated explanation of some aspect of the natural world, based on a body of facts that have been repeatedly confirmed through observation and experiment. Such fact-supported theories are not "guesses" but reliable accounts of the real world. Scientific theories are not ever proved in the sense of being proved to be 100% correct.

Examples of some scientific theories are ::

Evolution, gravity, atomic theory, the germ theory of disease, relativity, quantum theory, electromagnetic theory, layered Earth theory, etc...