Question

mendels pea plants had either purple or white flowers. this means that the plants
can self - pollinate.
have two recessive traits.
have two alleles for the gene.
have two copies of a gene from one parent.

Explanation:

In Mendelian genetics, for a trait like flower color in pea plants, each plant has two alleles for the gene (one from each parent). Alleles are different forms of a gene. Purple and white flower colors are determined by different alleles of the same gene. Self - pollination (option 1) is a reproductive method and not directly related to having two flower color options. Having two recessive traits (option 2) is incorrect as one of the traits (purple) is dominant. Having two copies of a gene from one parent (option 4) is wrong because in sexual reproduction (which Mendel's pea plants undergo), one allele comes from each parent.

Answer:

have two alleles for the gene.