Answer the following question given this paragraph: Enzymes are involved in most of the biochemical reactions that take place in organisms. About 4,000 such reactions are known to be catalyzed by enzymes, but the number may be even higher. Enzymes allow reactions to occur at the rate necessary for life. Q: What substances serve as catalysts in most of the biochemical reactions that take place in organisms? Choices: - hormones - carbohydrates - iseotrops - enzymes A:
enzymes
(Question)
Answer the following question given this paragraph: Over much of Earth's past, the climate was warmer than it is today. Picture in your mind dinosaurs roaming the land. They're probably doing it in a pretty warm climate! But ice ages also occurred many times in the past. An ice age is a period when temperatures are cooler than normal. This causes glaciers to spread to lower latitudes. Scientists think that ice ages occurred at least six times over the last billion years alone. How do scientists learn about Earth's past climates?. Q: What do you call a period when temperatures are cooler than normal, causing glaciers to spread? Choices: - polar age - earth age - thermal age - ice age A:
(Answer)
ice age
Ques: Answer the following question given this paragraph: wavelength : The distance between two crests of a wave of light. The color of light is related to its wavelength. This is inversely proportional to frequency. Q: The distance between two crests of a wave of light is referred to as what, which is related to the color of light? Choices: - magnitude - spectrum - bandwidth - wavelength A:
Ans: wavelength
(Q).
Answer the following question given this paragraph: The difference in electric potential energy is measured with a voltmeter in units called volts. Q: Difference in electric potential energy are measured in what basic unit? Choices: - moles - watts - knots - volts A:
(A).
volts
Ques:Answer the following question given this paragraph: An experiment generally tests how one variable is affected by another. The affected variable is called the dependent variable . In the plant experiment shown in the Figure above , the dependent variable is plant growth. The variable that affects the dependent variable is called the independent variable . In the plant experiment, the independent variable is fertilizersome plants will get fertilizer, others will not. In any experiment, other factors that might affect the dependent variable must be controlled. In the plant experiment, what factors do you think should be controlled? ( Hint: What other factors might affect plant growth?). Q: In a scientific experiment, the variable that is affected by the other one is called what? Choices: - effective variable - essential variable - independent variable - dependent variable A:

Ans:dependent variable
Ques: Answer the following question given this paragraph: 30.4 Leaves Leaves are the main site of photosynthesis. A typical leaf consists of a lamina (the broad part of the leaf, also called the blade) and a petiole (the stalk that attaches the leaf to a stem). The arrangement of leaves on a stem, known as phyllotaxy, enables maximum exposure to sunlight. Each plant species has a characteristic leaf arrangement and form. The pattern of leaf arrangement may be alternate, opposite, or spiral, while leaf form may be simple or compound. Leaf tissue consists of the epidermis, which forms the outermost cell layer, and mesophyll and vascular tissue, which make up the inner portion of the leaf. In some plant species, leaf form is modified to form structures such as tendrils, spines, bud scales, and needles. Q: What part of the plant is the main site of photosynthesis? Choices: - soil - root - stem - leaf A:
Ans:
leaf