Answer the following question given this paragraph: Unlike bones and tendons, which need to be strong as well as elastic, the arteries and lungs need to be very stretchable. The elastic properties of the arteries are essential for blood flow. The pressure in the arteries increases and arterial walls stretch when the blood is pumped out of the heart. When the aortic valve shuts, the pressure in the arteries drops and the arterial walls relax to maintain the blood flow. When you feel your pulse, you are feeling exactly thisthe elastic behavior of the arteries as the blood gushes through with each pump of the heart. If the arteries were rigid, you would not feel a pulse. The heart is also an organ with special elastic properties. The lungs expand with muscular effort when we breathe in but relax freely and elastically when we breathe out. Our skins are particularly elastic, especially for the young. A young person can go from 100 kg to 60 kg with no visible sag in their skins. The elasticity of all organs reduces with age. Gradual physiological aging through reduction in elasticity starts in the early 20s. Q: What causes reduction of elasticity in all organs? Choices: - low vitamin D - radiation - weight gain - age A:
age
Answer the following question given this paragraph: Features of continents include mountain ranges, plateaus, and plains. Q: Mountain ranges, plateaus, and plains are features of what large landforms? Choices: - Countries - planets - States - continents A:
continents
Q: Answer the following question given this paragraph: Plastids are membrane-bound organelles with their own DNA. Examples are chloroplasts and chromoplasts. Chloroplasts contain the green pigment chlorophyll and carry out photosynthesis . Chromoplasts make and store other pigments. They give flower petals their bright colors. Q: What are membrane-bound organelles with their own dna called? Choices: - vacuoles - chromosomes - ribosomes - plastids A:
A: plastids
Question: Answer the following question given this paragraph: Summary Bond order is the number of electron pairs that hold two atoms together. Single bonds have a bond order of one, and multiple bonds with bond orders of two (a double bond) and three (a triple bond) are quite common. In closely related compounds with bonds between the same kinds of atoms, the bond with the highest bond order is both the shortest and the strongest. In bonds with the same bond order between different atoms, trends are observed that, with few exceptions, result in the strongest single bonds being formed between the smallest atoms. Tabulated values of average bond energies can be used to calculate the enthalpy change of many chemical reactions. If the bonds in the products are stronger than those in the reactants, the reaction is exothermic and vice versa. Saylor URL: http://www. saylor. org/books. Q: The number of electron pairs that hold two atoms together is called? Choices: - nuclear order - proton order - electron order - bond order A:
Answer: bond order
*Question*
Answer the following question given this paragraph: Weight measures the force of gravity pulling downward on an object. The SI unit for weight, like other forces, is the Newton (N). On Earth, a mass of 1 kilogram has a weight of about 10 Newtons because of the pull of Earth's gravity. On the moon, which has less gravity, the same mass would weigh less. Weight is measured with a scale, like the spring scale shown in the Figure below . The scale measures the force with which gravity pulls an object downward. To delve a little deeper into weight and gravity, watch this video:. Q: What is the force that pulls downward on an object and is measured by weight? Choices: - strength - work - light - gravity A:
**Answer**
gravity
*Question*
Answer the following question given this paragraph: The gene theory is the idea that the characteristics of living organisms are controlled by genes, which are passed from parents to their offspring. A gene is a segment of DNA that has the instructions to encode a protein. Genes are located on larger structures, called chromosomes , that are found inside every cell. Chromosomes, in turn, contain large molecules known as DNA (deoxyribonucleic acid). Molecules of DNA are encoded with instructions that tell cells what to do. To see how this happens, click on the animation titled Journey into DNA at the following link: http://www. pbs. org/wgbh/nova/genome/dna. html . Q: Which theory is the idea that the characteristics of living organisms are controlled by genes, which are passed from parents to their offspring? Choices: - species theory - evolution theory - fossil theory - gene theory A:
**Answer**
gene theory