Cell theory has three basic tenets 1. All organisms are composed of one or more cells 2. The cell is basic unit of structure and function for all organIsms. 3. All cells arise only 区19. Schleiden(1804~1834) M 20.Schwann(1510-18s from preexisting cells by division
Cell theory has three basic tenets: 1. All organisms are composed of one or more cells. 2.The cell is basic unit of structure and function for all organisms. 3.All cells arise only from preexisting cells by division
3. Why are cells the basic units of life? A. The cell is the structural unit of life All organisms is make up of cells Doh mussa IntesTinal ermhnt al cers
3. Why are cells the basic units of life? A. The cell is the structural unit of life, All organisms is make up of cells
BThe cell is the functional unit of organisms All meta bolic activity is based on cells
B.The cell is the functional unit of organisms. All metabolic activity is based on cells
The cell is the foundation of reproduce and the bridge of inheritance
C. The cell is the foundation of reproduce, and the bridge of inheritance
D. The cell is the growing and developing basis of life I cm long 6 cm long 30 cm in length )5 weeks (b)14 weeks (c)20 weeks Human fetal development. (a)At 5 weeks, limb buds, eyes, the heart, the liver and rudiments of all other organs have started to develop in the embryo, which is only about lcm long. (b)Growth and development of the offspring, now called a fetus continue during the second trimester. This fetus is 14 weeks old and about 6cm long(cThe fetus in this photograph is 20 weeks old. Now the fetus grows to about 30cm in length
D. The cell is the growing and developing basis of life Human fetal development. (a)At 5 weeks, limb buds, eyes, the heart, the liver and rudiments of all other organs have started to develop in the embryo, which is only about 1cm long. (b)Growth and development of the offspring, now called a fetus, continue during the second trimester. This fetus is 14 weeks old and about 6cm long. (c)The fetus in this photograph is 20 weeks old. Now the fetus grows to about 30cm in length