Around 4.1 billion years ago the first single celled organism appeared
Explanation:
a.catalase
b.It plays important roles in host defense and oxidative biosynthetic reactions. In addition there is growing evidence that at low levels, H2O2 also functions as a signaling agent, particularly in higher organisms.
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Answer:organs
Explanation:the body of multicellular organisms are organised into levels of organization.these levels increases in complexity.
The macromolecules makes up the organelles . organelles in turn makes up the cell.A group of similar cells at a certain location makes up an organ.for example the heart consists of a number of cells.
A group of organs which work together to achieve a specific function in the body , makes up the organs system.
For example the circulatory system of a while is made up of different connected organs - heart, blood vessels,to perform the function of transporting blood around it's body.this makes it an organ system.
Bacterial flagellum is composed of protein flagellum which looks like hollow tube. It passes through protein rings (basal body rings) in the cell's membrane that act as bearings. Flagellum is long, filamentous and it rotates via motor which is located on the inner cell membrane. The motor is powered by proton motive force (flow of protons through the membrane due to a concentration gradient).
