Cyanobacteria, also known as blue-green algae, are found in vast quantities in fresh and salt water. Cyanobacteria are able to conduct photosynthesis. By utilising energy from the sun, they produce carbohydrates from water and carbon dioxide. As a byproduct, they produce oxygen. So cyanobacteria provided oxygen to the atmosphere that allowed other lifeforms to develop.
They have longer periods of revolution.
Answer:
Covalent
Explanation:
A covalent bond, also called a molecular bond, is a chemical bond that involves the sharing of electron pairs between atoms.
Answer: B and D
Explanation: We can break down why the correct answers are choices B and D by understanding why A and C are incorrect.
Option A states that active transport utilizes channel proteins, and facilitated diffusion utilizes carrier proteins. This is incorrect. Active transport involves carrier proteins, and facilitated diffusion involves channel proteins. Carrier proteins are different from channel proteins in that, while channel proteins can only facilitate the passive diffusion of ions into or out of the cell along their concentration gradient, carrier proteins can also use ATP to move ions in or out of the cell against their concentration gradient.
This brings us to why option C is also incorrect. Option C states that both processes require the input of energy in the form of ATP. While active transport requires the use of ATP to transport ions with or against their concentration gradient, facilitated diffusion does not. This is easily remembered when we consider that active transport is called *active* transport because the cell is *actively* using energy to transport ions.
Hope this helped.
