Q: Answer the following question given this paragraph: Hormones control many cell activities, so they are very important for homeostasis. But what controls the hormones themselves? Most hormones are regulated by feedback mechanisms. A feedback mechanism is a loop in which a product feeds back to control its own production. Most hormone feedback mechanisms involve negative feedback loops . Negative feedback keeps the concentration of a hormone within a narrow range. Q: Because they control many cell activities - as well as being controlled by feedback mechanisms - what substances are very important for homeostasis? Choices: - acids - proteins - enzymes - hormones A:
A: hormones

Q: Answer the following question given this paragraph: Animals and Plants: Herbivory Coevolution of flowering plants and insects is a hypothesis that has received much attention and support, especially because both angiosperms and insects diversified at about the same time in the middle Mesozoic. Many authors have attributed the diversity of plants and insects to pollination and herbivory, or consumption of plants by insects and other animals. This is believed to have been as much a driving force as pollination. Coevolution of herbivores and plant defenses is observed in nature. Unlike animals, most plants cannot outrun predators or use mimicry to hide from hungry animals. A sort of arms race exists between plants and herbivores. To "combat" herbivores, some plant seedssuch as acorn and unripened persimmonare high in alkaloids and therefore unsavory to some animals. Other plants are protected by bark, although some animals developed specialized mouth pieces to tear and chew vegetal material. Spines and thorns (Figure 26.18) deter most animals, except for mammals with thick fur, and some birds have specialized beaks to get past such defenses. Q: What hypothetical link between development of herbivores and plant defenses is observed in nature, for instance in seeds that are unsavory to animals? Choices: - interconnection - abjection - natural selection - coevolution A:
A: coevolution

Q: Answer the following question given this paragraph: Kinetic energy is the energy of moving matter. Anything that is moving has kinetic energyfrom atoms in matter to stars in outer space. Things with kinetic energy can do work. For example, the spinning saw blade in the photo above is doing the work of cutting through a piece of metal. Q: What type of energy is the energy of moving matter? Choices: - dynamic energy - residual energy - potential energy - kinetic energy A:
A: kinetic energy

Q: Answer the following question given this paragraph: Caecilians The caecilian order is the amphibian order with the fewest species. Caecilians are closely related to salamanders. They have a long, worm-like body. They are the only amphibians without legs. Caecilians evolved from a four-legged ancestor but lost their legs later in their evolution. As adults, they often burrow into the soil. That's one reason why Caecilians tend to be less well known than other amphibians. microcaecilia. Q: What are the only amphibians without legs? Choices: - newts - crustaceans - porifera - caecilians A:
A: caecilians