Q: How long do the long-lived isotopes require to decay to a safe level in a nuclear reactor? Read this paragraph and choose the correct option from the provided answers: The energy produced by a reactor fueled with enriched uranium results from the fission of uranium as well as from the fission of plutonium produced as the reactor operates. As discussed previously, the plutonium forms from the combination of neutrons and the uranium in the fuel. In any nuclear reactor, only about 0.1% of the mass of the fuel is converted into energy. The other 99.9% remains in the fuel rods as fission products and unused fuel. All of the fission products absorb neutrons, and after a period of several months to a few years, depending on the reactor, the fission products must be removed by changing the fuel rods. Otherwise, the concentration of these fission products would increase and absorb more neutrons until the reactor could no longer operate. Spent fuel rods contain a variety of products, consisting of unstable nuclei ranging in atomic number from 25 to 60, some transuranium elements, including plutonium and americium, and unreacted uranium isotopes. The unstable nuclei and the transuranium isotopes give the spent fuel a dangerously high level of radioactivity. The long-lived isotopes require thousands of years to decay to a safe level. The ultimate fate of the nuclear reactor as a significant source of energy in the United States probably rests on whether or not a politically and scientifically satisfactory technique for processing and storing the components of spent fuel rods can be developed. Choices: - tens of years - millions of years - hundreds of years - thousands of years A:
thousands of years

Q: What is measured by the intensity of the sound waves? Read this paragraph and choose the correct option from the provided answers: Loudness refers to how loud or soft a sound seems to a listener. The loudness of sound is determined, in turn, by the intensity of the sound waves. Intensity is a measure of the amount of energy in sound waves. The unit of intensity is the decibel (dB) . Choices: - inputs - tone - pitch - loudness A:
loudness

Q: Q: Melting ice and grinding wood into sawdust are examples of what? Read this paragraph and choose the correct option from the provided answers: Melting ice and grinding wood into sawdust are examples of physical changes. Choices: - chemical changes - reversible changes - unpredictable changes - physical changes A:
A: physical changes

Question: Q: What emerges from an insect egg? Read this paragraph and choose the correct option from the provided answers: When an insect egg hatches, a larva emerges. The larva eats and grows and then enters the pupa stage. The pupa is immobile and may be encased in a cocoon . During the pupa stage, the insect goes through metamorphosis . Tissues and appendages of the larva break down and reorganize into the adult form. How did such an incredible transformation evolve? Metamorphosis is actually very advantageous. It allows functions to be divided between life stages. Each stage can evolve adaptations to suit it for its specific functions without affecting the adaptations of the other stage. Choices: - cocoon - fungi - parasite - larva A:
Answer: larva

*Question*
Q: Consumers are organisms that depend on other organisms for what? Read this paragraph and choose the correct option from the provided answers: Consumers are organisms that depend on other organisms for food. They take in organic molecules by essentially "eating" other living things. They include all animals and fungi. (Fungi don't really "eat"; they absorb nutrients from other organisms. ) They also include many bacteria and even a few plants, such as the pitcher plant in Figure below . Consumers are also called heterotrophs. Heterotrophs are classified by what they eat:. Choices: - knowledge - reproduction - shelter - food A:
**Answer**
food

(Q).
Q: What term describes the overall ability of an animal to survive and produce offspring? Read this paragraph and choose the correct option from the provided answers: Animal communication, like most other animal behaviors, increases the ability to survive and have offspring. This is known as fitness. Communication increases fitness by helping animals find food, defend themselves from predators, mate, and care for offspring. Choices: - change - evolution - abilities - fitness A:
(A).
fitness