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How many cell layers is the lower epidermis composed of?

In addition to protecting the rest of the leaf, the lower epidermis contains the majority of the stomata on the leaf. Stomata are tiny pores in the bottom of the leaf protected by guard cells. The stomata are necessary to exchange gas with the outside environment. The plant uses stomata to take in carbon dioxide for photosynthesis and expel oxygen.

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What are some facts about the Golgi apparatus?

The Golgi apparatus is an essential part of the cellular endomembrane system. It packages proteins inside of the cell and prepares them for secretion out of the cell. The organelle is composed of a series of cylindrical membranes. It has a cell membrane that is two layers thick and absorbs proteins from the endoplasmic reticulum. The proteins from the endoplasmic reticulum are packaged together to make them more complex. Once the organelle has processed the proteins, it can store them in vesicles. The vesicles can be dormant for a long time, or they can be secreted from the cell. When secreted..

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What are some examples of opaque objects?

When light strikes an opaque object it is either absorbed by the object or it is bounced off or reflected by the object. For example, white objects reflect light, which is why they are cooler to the touch. Dark objects absorb light and transform it into heat. Other objects absorb some wavelengths of light while deflecting others.

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How long will natural gas reserves last?

The United States' natural gas reserves consist of around 2,203 trillion cubic feet of technically recoverable natural gas. Technically recoverable energy reserves refer to those that are retrievable using contemporary technology, as well as those whose production is already expected given already existing economic conditions. The estimate for how long natural gas reserves in the United States will last is based on both the expected production and any other available energy.

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How is potassium used?

WebMD explains that potassium is important in nerve signal transmission, fluid balance, muscle contractions and numerous chemical reactions. Some people use this mineral for treating infant colic, insulin resistance, thallium poisoning, Meniere’s disease, high calcium levels and symptoms of menopause. Additionally, people use it to treat headaches, allergies, alcoholism, acne and Alzheimer’s disease among other diseases and conditions. Health care providers treat and prevent low potassium levels, heart attack and irregular heartbeats by supplying potassium intravenously to a patient.\nPota..

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What causes waves?

Waves are the forward motion of water. Waves reach down to the ocean floor, and only a portion of a wave is visible on the surface. Waves are initially formed out in the open ocean, beginning as generally vertical in shape.\nAs the wave travels toward the shore, the lower section drags the bottom of the ocean floor. The surface section of the wave moves faster than the submerged portion. As the wave reaches the more shallow water levels near the shore, the drag of the seafloor increases, slowing the underwater section of the wave even more, causing the wave to tilt forward. The rolling wave ev..

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What causes the smell after rain?

The first key word to understanding rain’s distinct smell is petrichor, or molecules in the air that come from decomposed animal or plant materials. These particles settle on hard surfaces like rock, clay, concrete, or asphalt. When the rain comes, the petrichor releases chemicals back into the air, giving the surroundings a unique odor.Another element that contributes to the rain’s smell is the (equally difficult to pronounce) chemical geosmin, which is a waste product of bacteria and blue-green algae. When combined with water, geosmin releases an earthy smell that is similar to soil. Thi..

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Is the Earth's core hotter than the sun?

An upper layer of the sun’s atmosphere called the photosphere has a temperature of about 10,000 F. If one compares this temperature to the Earth’s core temperature, which is approximately 10,800 F, one finds that the Earth’s core is hotter than this layer of the sun’s surface.\nHowever, the sun’s core temperature can be as high as 27 million F. If one compares this to Earth’s core temperature of 10,800 degrees Fahrenheit, then the sun’s core temperature is much hotter than that of the Earth’s core.

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What type of sedimentary rock is permeable?

All permeable rocks have relatively high porosity, which is the percentage of the rock's volume that consists of open space. Sedimentary rocks consisting of well-rounded coarse grains are usually porous; fine-grained rocks and rocks made of poorly sorted sediments have low porosity because the fine grains fill in most of the available space. Cements or binding agents also fill in pore space. For rock to be permeable, pores must be interconnected with large enough channels to permit the passage of water.

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Could humans ever travel at warp speed?

Experts still don't know how warp travel would affect the human body. Some warp speed theories include the use of a "warp bubble," but that may cause damage to human tissue. Based on where technology stands now, it's likely that humans could reach warp-speed travel toward the end of 21st century at the very earliest.

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