What are the main characteristics of living things?

(1) Living things need nutrition.

(2) living things can breathe.

(3) Organisms can excrete wastes produced in the body.

(4) Organisms can respond to external stimuli.

(5) Organisms can grow and reproduce.

(6) All living things except viruses are made up of cells.

Cells are the cornerstone of the structural hierarchy of life systems. Without cells, there would be no magical life movement, let alone the magnificent picture of life on earth.

From biosphere to cell, life system is interdependent and has its own specific composition, structure and function.

Material basis: the composition of matter and elements (same species) is basically the same.

(1) compounds are mainly protein and nucleic acid, in which protein is the main undertaker of life activities, and nucleic acid is the carrier of genetic information (the genetic material of prion is protein), and they are all important macromolecules in life activities.

(2) Elements are divided into constant elements and trace elements, among which the constant elements are C, H, O, N, P, S, K, Ca, Mg, etc. , plays a huge role in life activities; Trace elements such as iron, manganese, zinc, copper, boron and molybdenum. It has the characteristics of less dosage and good effect.

Structural basis: Except viruses, they are all composed of cells (viruses need to rely on living cells for life activities).

Extended data:

A living organism with kinetic energy is also a collection of objects, while an individual organism refers to an organism, as opposed to an abiotic one.

Its elements include: living beings with viability and reproductive ability produced by chemical reactions under natural conditions, and living offspring that can respond to external stimuli and rely on and promote each other with the external environment through reproduction. But also can excrete useless substances in the body, which has the characteristics of heredity and variation.

A large number of elements make up cells, such as C, H, O, N, P, S, K, Ca, Mg, etc. Some of these elements are components of cells, while others are necessary to maintain normal life activities of cells. For example, C, H, O, and N are all essential elements of life and protein.

References:

Baidu encyclopedia-biology