Final answer:
Organisms that contain cells from two different lineages are called chimeras, which have cells with different sets of DNA. Meiosis facilitates the alternation of generations but is not directly involved in the production of gametes from haploid gametophytes. Somatic cells are diploid as they possess double the number of chromosomes than haploid gametes.
Step-by-step explanation:
Chimeras in Biology
Organisms that contain cells from two different lineages are known as chimeras. The term chimera originates from a creature in Greek mythology composed of parts from various animals. In biology, a chimera is an organism that has cells from two different zygotes, meaning it has two or more different sets of DNA. Chimerism can happen naturally or be induced scientifically. In contrast, chiasmata are related to genetics, specifically the points where two homologous non-sister chromatids exchange genetic material during meiotic cell division.
Alternation of generations is a phenomenon in life cycles where an organism has both haploid and diploid multicellular stages. Meiosis and fertilization alternate to create these different stages. The diploid phase produces spores by meiosis that develop into multicellular haploid organisms called gametophytes. These gametophytes then produce gametes through mitosis, a process not involving meiosis since gametophytes are already haploid.
In terms of cellular organization, somatic cells are body cells and typically have double the number of chromosomes than reproductive cells, known as gametes. This is because somatic cells are diploid, containing homologous chromosomes from each parent, while gametes are haploid, having just one set of chromosomes. In animals with complex body plans, cells may exhibit radial symmetry or bilateral symmetry and are divided into groups based on their developmental patterns, such as protostomes and deuterostomes.
In conclusion, the correct answer to the question of what organisms that contain cells from 2 different lineages are called is (A) Chimeras.