It's nucleus is positively charged because of protons.
The correct answer is option B, that is, the respiratory and circulatory systems.
The respiratory and circulatory system functions together to circulate oxygen and blood all through the body. The movement of air takes place in and out of the lungs via the bronchi, trachea, and bronchioles. The movement of blood takes place in and out of the lungs via the pulmonary veins and arteries, which associate with the heart.
The pulmonary arteries mediate deoxygenated blood to the lungs from the heart, and the pulmonary veins carry oxygenated blood to the heart again so that it can be distributed to the rest of the body.
69. The student's skin was obviously warmer than the initial temperature of the bracelet. According to the second law of thermodynamics, heat transfers from a higher temperature to a lower temperature hence heat transfers from the student's skin to the bracelet warming up the bracelet.
70. moles of copper=mass of copper/molar mass of copper
=30.1g/(63.55g/mol)= 0.4736 moles Cu
71. Delta H( heat released) = mCp(deltaT) = 30.1g(0.385 J/gK)(33-19)K = 162.23J
72. Copper is chemically less active than iron.
37.5 for median ( first organize from least to greatest, elimate from each side until you get to center then add two numbers and divide by two.) Hope that helps.
