Answer the following question given this paragraph: Q: What is the predominant stage in the life cycle of most scyphozoans? Choices: - hydra - spore - gamete - medusa A:
medusa
Answer the following question given this paragraph: 15.3 Flatworms, Nematodes, and Arthropods Flatworms are acoelomate, triploblastic animals. They lack circulatory and respiratory systems, and have a rudimentary excretory system. The digestive system is incomplete in most species. There are four traditional classes of flatworms, the largely free-living turbellarians, the ectoparasitic monogeneans, and the endoparasitic trematodes and cestodes. Trematodes have complex life cycles involving a secondary mollusk host and a primary host in which sexual reproduction takes place. Cestodes, or tapeworms, infect the digestive systems of primary vertebrate hosts. Nematodes are pseudocoelomate members of the clade Ecdysozoa. They have a complete digestive system and a pseudocoelomic body cavity. This phylum includes free-living as well as parasitic organisms. They include dioecious and hermaphroditic species. Nematodes have a poorly developed excretory system. Embryonic development is external and proceeds through larval stages separated by molts. Arthropods represent the most successful phylum of animals on Earth, in terms of number of species as well as the number of individuals. They are characterized by a segmented body and jointed appendages. In the basic body plan, a pair of appendages is present per body segment. Within the phylum, classification is based on mouthparts, number of appendages, and modifications of appendages. Arthropods bear a chitinous exoskeleton. Gills, tracheae, and book lungs facilitate respiration. Embryonic development may include multiple larval stages. Q: What phylum has the highest number of species on earth? Choices: - lophotrochozoa - cephalopods - lichens - arthropods A:
arthropods
Q: Answer the following question given this paragraph: Invertebrate Digestive Systems Animals have evolved different types of digestive systems to aid in the digestion of the different foods they consume. The simplest example is that of a gastrovascular cavity and is found in organisms with only one opening for digestion. Platyhelminthes (flatworms), Ctenophora (comb jellies), and Cnidaria (coral, jelly fish, and sea anemones) use this type of digestion. Gastrovascular cavities, as shown in Figure 34.5a, are typically a blind tube or cavity with only one opening, the "mouth", which also serves as an "anus". Ingested material enters the mouth and passes through a hollow, tubular cavity. Cells within the cavity secrete digestive enzymes that break down the food. The food particles are engulfed by the cells lining the gastrovascular cavity. The alimentary canal, shown in Figure 34.5b, is a more advanced system: it consists of one tube with a mouth at one end and an anus at the other. Earthworms are an example of an animal with an alimentary canal. Once the food is ingested through the mouth, it passes through the esophagus and is stored in an organ called the crop; then it passes into the gizzard where it is churned and digested. From the gizzard, the food passes through the intestine, the nutrients are absorbed, and the waste is eliminated as feces, called castings, through the anus. Q: The simplest example of what type of 'organ system' is the gastrovascular cavity found in organisms with only one opening for the process? Choices: - cardiovascular - respiratory - nervous - digestive A:
A: digestive
Question: Answer the following question given this paragraph: A compound is a substance that consists of two or more elements. A compound has a unique composition that is always the same. The smallest particle of a compound is called a molecule. Q: What is the smallest part of a compound? Choices: - electron - dna - nucleus - molecule A:
Answer: molecule
*Question*
Answer the following question given this paragraph: 21.6 Comparing genome sequences provides clues to evolution and development. Q: Comparing what sequences provides clues to evolution and development? Choices: - DNA - genes - organisms - genome A:
**Answer**
genome
*Question*
Answer the following question given this paragraph: When a sperm penetrates the egg, it triggers the egg to complete meiosis. The sperm also undergoes changes. Its tail falls off, and its nucleus fuses with the nucleus of the egg. The resulting cell, called a zygote, contains all the chromosomes needed for a new human organism. Half the chromosomes come from the egg and half from the sperm. Q: When a sperm penetrates the egg, it triggers the egg to complete what? Choices: - mutations - fertilization - lesions - meiosis A:
**Answer**
meiosis