Ques:Q: What organism is at the top of the energy pyramid? Read this paragraph and choose the correct option from the provided answers: Each step of the food chain in the energy pyramid is called a trophic level . Plants or other photosynthetic organisms ( autotrophs ) are found on the first trophic level, at the bottom of the pyramid. The next level will be the herbivores, and then the carnivores that eat the herbivores. The energy pyramid ( Figure below ) shows four levels of a food chain, from producers to carnivores. Because of the high rate of energy loss in food chains, there are usually only 4 or 5 trophic levels in the food chain or energy pyramid. There just is not enough energy to support any additional trophic levels. Heterotrophs are found in all levels of an energy pyramid other than the first level. Choices: - primate - herbivore - insects - carnivore A:

Ans:carnivore
-----
Ques:Q: Which metal is not a solid even at room temperature? Read this paragraph and choose the correct option from the provided answers: A metal is an element that is a good conductor of heat and electricity. Metals are also malleable, which means that they can be hammered into very thin sheets without breaking, and ductile, which means that they can be drawn into wires. When a fresh surface of any metal is exposed, it will be very shiny, because it reflects light well. This property is referred to as luster. All metals are solid at room temperature except mercury (Hg), which is a liquid. The melting points of different metals vary widely. Mercury has the lowest melting point of all pure metals (39C), and tungsten (W) has the highest (3422C). On the periodic table in Figure above , the metals are shaded blue and are located to the left of the bold stair-step line. About 80 percent of the elements are metals (see examples in Figure below ). Choices: - iron - copper - aluminum - mercury A:

Ans:mercury
-----
Ques:Q: What is the term for a theoretical framework for describing evolutionary change in populations through the change in allele frequencies? Read this paragraph and choose the correct option from the provided answers: CHAPTER SUMMARY 11.1 Discovering How Populations Change Evolution by natural selection arises from three conditions: individuals within a species vary, some of those variations are heritable, and organisms have more offspring than resources can support. The consequence is that individuals with relatively advantageous variations will be more likely to survive and have higher reproductive rates than those individuals with different traits. The advantageous traits will be passed on to offspring in greater proportion. Thus, the trait will have higher representation in the next and subsequent generations leading to genetic change in the population. The modern synthesis of evolutionary theory grew out of the reconciliation of Darwin's, Wallace's, and Mendel's thoughts on evolution and heredity. Population genetics is a theoretical framework for describing evolutionary change in populations through the change in allele frequencies. Population genetics defines evolution as a change in allele frequency over generations. In the absence of evolutionary forces allele frequencies will not change in a population; this is known as Hardy-Weinberg equilibrium principle. However, in all populations, mutation, natural selection, genetic drift, and migration act to change allele frequencies. Choices: - percent genetics - density genetics - total genetics - population genetics A:

Ans:population genetics
-----
Ques:Q: Why are the stems of many xerophytes fleshy? Read this paragraph and choose the correct option from the provided answers: Choices: - drains water - pressures water - collects water - stores water A:

Ans:
stores water
-----