Given a scientific passage and an answer, generate a question for the given answer.

[Q]: Passage: There are multiple ways to prevent these situations from occurring. The three most common protective devices are fuses, circuit breakers, and surge protectors. Answer: fuses, circuit breaks & surge protectors
[A]: What are the three most common protective devices?

[Q]: Passage: CHAPTER SUMMARY 30.1 The Plant Body A vascular plant consists of two organ systems: the shoot system and the root system. The shoot system includes the aboveground vegetative portions (stems and leaves) and reproductive parts (flowers and fruits). The root system supports the plant and is usually underground. A plant is composed of two main types of tissue: meristematic tissue and permanent tissue. Meristematic tissue consists of actively dividing cells found in root and shoot tips. As growth occurs, meristematic tissue differentiates into permanent tissue, which is categorized as either simple or complex. Simple tissues are made up of similar cell types; examples include dermal tissue and ground tissue. Dermal tissue provides the outer covering of the plant. Ground tissue is responsible for photosynthesis; it also supports vascular tissue and may store water and sugars. Complex tissues are made up of different cell types. Vascular tissue, for example, is made up of xylem and phloem cells. Answer: permanent tissue
[A]: A plant is composed of two main types of tissue: meristematic tissue and what other kind of tissue?

[Q]: Passage: During crossing-over, segments of DNA are exchanged between non-sister chromatids of homologous chromosomes. Notice how this can result in an allele (A) on one chromosome being moved to the other chromosome. The four chromatids compose the tetrad, with a chiasma at the point of exchange. Answer: during crossing-over
[A]:
When does exchange of dna segments happen between non-sister chromatids of homologous chromosomes?