Answer the following question given this paragraph: In shallow water close to shore, waves start to drag on the bottom of the water. The bottomsbut not the topsof the wave slow down because of friction. This causes the waves to steepen until they break and fall over, carrying water onto the shore as surf. Q: The bottomsbut not the topsof the wave slow down because of what? Choices: - size - vibration - temperature - friction A:
friction
Answer the following question given this paragraph: In addition to producing FSH and LH, the anterior portion of the pituitary gland also produces the hormone prolactin (PRL) in females. Prolactin stimulates the production of milk by the mammary glands following childbirth. Prolactin levels are regulated by the hypothalamic hormones prolactin-releasing hormone (PRH) and prolactin-inhibiting hormone (PIH), which is now known to be dopamine. PRH stimulates the release of prolactin and PIH inhibits it. The posterior pituitary releases the hormone oxytocin, which stimulates uterine contractions during childbirth. The uterine smooth muscles are not very sensitive to oxytocin until late in pregnancy when the number of oxytocin receptors in the uterus peaks. Stretching of tissues in the uterus and cervix stimulates oxytocin release during childbirth. Contractions increase in intensity as blood levels of oxytocin rise via a positive feedback mechanism until the birth is complete. Oxytocin also stimulates the contraction of myoepithelial cells around the milk-producing mammary glands. As these cells contract, milk is forced from the secretory alveoli into milk ducts and is ejected from the breasts in milk ejection ("let-down") reflex. Oxytocin release is stimulated by the suckling of an infant, which triggers the synthesis of oxytocin in the hypothalamus and its release into circulation at the posterior pituitary. Q: The posterior pituitary releases which hormone, which stimulates uterine contractions during childbirth? Choices: - estrogen - insulin - estradiol - oxytocin A:
oxytocin
Q: Answer the following question given this paragraph: During a nuclear decay process that occurs by positron emission, a proton is converted into a neutron and a positron. The neutron remains in the nucleus, and the positron is expelled. Overall, the atomic number of the parent nucleus increases by one, and the mass number is unchanged. For example, carbon-11 emits a positron to become boron-11:. Q: What happens to the mass number during a nuclear decay process by positron emission? Choices: - it rises - it decreases - it increases - remains unchanged A:
A: remains unchanged
Question: Answer the following question given this paragraph: Comets are small, icy objects that orbit the Sun in very elliptical orbits. When they are close to the Sun, they form comas and tails, which glow and make the comet more visible. Q: What types of orbits do comets usually have? Choices: - vertical - convex - spectral - elliptical A:
Answer: elliptical
*Question*
Answer the following question given this paragraph: Typically, a series of several mutations that constitutively activate oncogenes and inactivate tumor suppressor genes is required to transform a normal cell into a cancer cell ( Figure below ). Cells have developed a number of control mechanisms to overcome mutations in proto-oncogenes. Therefore, a cell needs multiple mutations to transform into a cancerous cell. A mutation in one proto-oncogene would not cause cancer, as the effects of the mutation would be masked by the normal control of the cell cycle and the actions of tumor suppressor genes. Similarly, a mutation in one tumor suppressor gene would not cause cancer either, due to the presence of many "backup" genes that duplicate its functions. It is only when enough proto-oncogenes have mutated into oncogenes and enough tumor suppressor genes have been deactivated that the cancerous transformation can begin. Signals for cell growth overwhelm the signals for growth regulation, and the cell quickly spirals out of control. Often, because many of these genes regulate the processes that prevent most damage to the genes themselves, DNA damage accumulates as one ages. Q: What does a cell need to transform into a cancerous cell? Choices: - microbes - parasites - adaptations - mutations A:
**Answer**
mutations
Answer the following question given this paragraph: All chemical changes involve a transfer of energy. When zinc reacts with hydrochloric acid, the test tube becomes very warm as energy is released during the reaction. Some other reactions absorb energy. While energy changes are a potential sign of a chemical reaction, care must be taken to ensure that a chemical reaction is indeed taking place. Physical changes may also involve a transfer of energy. A solid absorbs energy when it melts, and the condensation of a gas releases energy. The only way to be certain that a chemical reaction has occurred is to test the composition of the substances after the change has taken place to see if they are different from the starting substances. Q: All chemical changes involve a transfer of what? Choices: - heating - fuel - Water - energy A:
energy