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

[Q]: Passage: 19.4 Community Ecology Communities include all the different species living in a given area. The variety of these species is referred to as biodiversity. Many organisms have developed defenses against predation and herbivory, including mechanical defenses, warning coloration, and mimicry. Two species cannot exist indefinitely in the same habitat competing directly for the same resources. Species may form symbiotic relationships such as commensalism, mutualism, or parasitism. Community. Answer: symbiotic
[A]: Commensalism, mutualism, and parasitism are known as what type of relationships?

[Q]: Passage: The Prokaryotic Cell Recall that prokaryotes (Figure 22.10) are unicellular organisms that lack organelles or other internal membrane-bound structures. Therefore, they do not have a nucleus but instead generally have a single chromosomea piece of circular, double-stranded DNA located in an area of the cell called the nucleoid. Most prokaryotes have a cell wall outside the plasma membrane. Answer: nucleoid
[A]: Prokaryotic cells do not have a nucleus but instead generally have a single chromosome, a piece of double-stranded dna located in an area of the cell called the what?

[Q]: Passage: In ordinary chemical reactions, the nucleus of each atom (and thus the identity of the element) remains unchanged. Electrons, however, can be added to atoms by transfer from other atoms, lost by transfer to other atoms, or shared with other atoms. The transfer and sharing of electrons among atoms govern the chemistry of the elements. During the formation of some compounds, atoms gain or lose electrons, and form electrically charged particles called ions (Figure 2.28). Answer: ions
[A]:
When atoms gain or lose electrons, they can form electrically charged particles called what?