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HighFour General Sciences Category B: Grades 6 – 8 Round 6 Tuesday, February 14, 2017 The use of calculator is not required. Answer #1 Explanation: A The moon orbits the Earth once every 27.322 days. It also takes approximately 27 days for the moon to rotate once on its axis. As a result, the moon does not seem to be spinning but appears to observers from Earth to be keeping almost perfectly still. Scientists call this synchronous rotation. Answer #2 Explanation: A To calculate the mass given the density and the volume, we use the formula . The mass of 2 m3 of clay bricks is kg, which is the lowest of the ones listed. Answer #3 Explanation: B Reflection is when light bounces off an object. If the surface is smooth and shiny, like glass, water or polished metal, the light will reflect at the same angle as it hit the surface. This is called specular reflection. Answer #4 Explanation: D In biology and ecology, extinction is the end of an organism or of a group of organisms (taxon), normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point. Answer #5 Explanation: C In 1875, the trench was discovered by the HMS Challenger using recently invented sounding equipment during a global circumnavigation. In 1951, the trench was sounded again by HMS Challenger II. In 1960, a "deep boat" named Bathyscaphe Trieste reached the bottom of Challenger Deep. HighFour General Sciences Category B: Grades 6 – 8 Round 6 Tuesday, February 14, 2017 The use of calculator is not required. Answer #6 Explanation: B Plants use energy from sunlight to turn water and carbon dioxide into an energy-rich sugar called glucose. This process is called photosynthesis, which means “making things with light”. Photosynthesis takes place inside capsules in the leaf cells, called chloroplasts. Answer #7 Explanation: C Aquatic plants are plants that have adapted to living in aquatic environments (saltwater or freshwater). They are also referred to as hydrophytes or macrophytes. These plants require special adaptations for living submerged in water, or at the water's surface. Answer #8 Explanation: A The muscular system is responsible for the movement of the human body. Attached to the bones of the skeletal system are about 700 named muscles that make up roughly half of a person's body weight. Each of these muscles is a discrete organ constructed of skeletal muscle tissue, blood vessels, tendons, and nerves. Answer #9 Explanation: B The lithosphere is the solid, outer part of the Earth. The lithosphere includes the brittle upper portion of the mantle and the crust, the outermost layers of Earth's structure. It is bounded by the atmosphere above and the asthenosphere (another part of the upper mantle) below. Answer #10 Explanation: D Non-renewable energy comes from sources that will run out or will not be replenished in our lifetimes—or even in many, many lifetimes. Most non-renewable energy sources are fossil fuels: coal, petroleum, and natural gas. Carbon is the main element in fossil fuels. HighFour General Sciences Category B: Grades 6 – 8 Round 6 Tuesday, February 14, 2017 The use of calculator is not required. Answer #11 Explanation: D Fertilization is the process by which a sperm cell and an egg cell unite to form a completely new individual. The difference between internal and external fertilization is that internal fertilization occurs inside the body, whereas external fertilization happens outside the body. In mammals, reptiles, birds, and some types of fish the gametes meet inside of the female's body. Answer #12 Explanation: B Genetic engineering, also called genetic modification, is the direct manipulation of an organism's genome using biotechnology. It is a set of technologies used to change the genetic makeup of cells, including the transfer of genes within and across species boundaries to produce improved or novel organisms. Answer #13 Explanation: B Drilling began on May 24th, 1970 in the Kola Peninsula and continued breaking records of all sorts. Many holes were drilled branching from the center. The deepest of these holes is the hole SG-3, which reached a depth of 12,262 meters (more than 40,000 ft) in 1989. Answer #14 Explanation: D During the process of absorption, nutrients that come from the food (including carbohydrates, proteins, fats, vitamins, and minerals) pass through channels in the intestinal wall and into the bloodstream. The blood works to distribute these nutrients to the rest of the body. Answer#15 Explanation: A Objects have mechanical energy if they are in motion and/or if they are at some position relative to a zero potential energy position (for example, a brick held at a vertical position above the ground or zero height position). A moving car possesses mechanical energy due to its motion (kinetic energy). HighFour General Sciences Category B: Grades 6 – 8 Round 6 Tuesday, February 14, 2017 The use of calculator is not required. Answer #16 Explanation: A Sandstone (sometimes known as arenite) is a clastic sedimentary rock composed mainly of sand-sized minerals or rock grains. Most sandstone is composed of quartz or feldspar because these are the most common minerals in the Earth's crust. Answer #17 Explanation: C Galaxies are divided into four main groups: spiral, barred spiral, elliptical, and irregular. Spiral Galaxy – Spiral galaxies are characterized by a distinct flattened spiral disk with a bright center called the nucleus. Our own Milky Way is a spiral galaxy. Answer #18 Explanation: B A unicellular organism, also known as a single-celled organism, is an organism that consists of only one cell, unlike a multicellular organism that consists of more than one cell. The main groups of unicellular organisms are bacteria, archaea, protozoa, unicellular algae, and unicellular fungi. Unicellular organisms fall into two general categories: prokaryotic organisms and eukaryotic organisms. Answer #19 Explanation: B Galileo Galilei is commonly credited for inventing the telescope, but this is not accurate. Galileo was the first to use a telescope for the purpose of astronomy in 1609, although the earliest known working telescopes appeared in 1608 in the Netherlands and are credited to Hans Lippershey. Answer #20 Explanation: D Sedimentary rocks are types of rock that are formed by the deposition and subsequent cementation of that material at the Earth's surface and within bodies of water. Sedimentation is the collective name for processes that cause mineral and/or organic particles (detritus) to settle in place.