The picture shows the genetic diagram of pea color. According to the analysis of the picture, (1) the parents of peas are all purple flowers, but white flowers appear in their offspring. This phenomenon is in biology. (1) The difference of traits between offspring and parents and between offspring individuals is called variation. The similarity of traits between parents and offspring is genetic, so there is still purple flower in offspring, which is biologically called heredity. The morphological characteristics, physiological characteristics and behavior of organisms are called traits, and the different manifestations of the same trait of the same species are called relative traits. Purple flower and white flower of pea are different manifestations of the same trait of the same organism and belong to relative traits.

(2) If there are traits in the offspring that the parents don't have, the new traits are recessive traits, because recessive traits are not easy to show, and only when two recessive genes meet will they show recessive traits. Therefore, purple flowers can be judged as dominant traits according to the performance rules of pea colors in parents and offspring.

(3) Some traits of an organism are controlled by a pair of genes, and the paired genes are often dominant and recessive. When a pair of genes controlling a trait in a cell is dominant and recessive, only the traits controlled by the dominant genes will be displayed. One of the genes controlling a trait in the offspring comes from the father and the other from the mother. The white flower in the offspring is a recessive trait, and its genome becomes aa, indicating that both purple flowers contain one.

(4) Chromosomes exist in pairs in somatic cells. In the process of reproduction, a special way of cell division is required, resulting in a reduction of the number of chromosomes in germ cells by half.

(5) It can be seen from the genetic diagram of (3) that the probability of inferring white offspring is 25% or14 theoretically.

Therefore, the answer is: (1) variation; Heredity; Relative character; (2) purple flowers; （3）Aa； Aa； AA、Aa； aa； (4) in pairs; Halve; (5)25% or14.