The basic point of impact by changes which produce mutation is the

Explanation

The question is asking where mutations occur in an organism. Mutations are changes in the genetic material of an organism, and they can happen spontaneously or as a result of exposure to certain environmental factors such as radiation or chemicals. The question provides four options to choose from, and we are asked to select the basic point of impact by changes which produce mutation. The first option is gametes. Gametes are the reproductive cells of an organism, such as sperm and egg cells in animals and pollen and ovules in plants. Mutations that occur in gametes can be passed on to the next generation and can lead to genetic disorders or variations. The second option is chromosomes, which is the correct answer. Chromosomes are thread-like structures that contain the genetic material of an organism in the form of DNA. Mutations can occur in the DNA of chromosomes and can lead to changes in the traits of an organism. Chromosomal mutations can result in genetic disorders such as Down Syndrome. The third option is phenotype. Phenotype refers to the physical and observable characteristics of an organism, such as its height, eye color, or behavior. Mutations that affect phenotype can result in variations in traits, but they do not occur at the basic point of impact. The fourth option is zygote. A zygote is a fertilized egg cell that contains the genetic material from both parents. Mutations can occur in the DNA of a zygote, but they do not occur at the basic point of impact. Therefore, the correct answer to this question is option B, chromosomes. Mutations occur in the DNA of chromosomes and can lead to changes in the traits of an organism.