Q: Q: What is the largest of the sinuses? Read this paragraph and choose the correct option from the provided answers: Venous Drainage of the Brain Circulation to the brain is both critical and complex (see Figure 20.37). Many smaller veins of the brain stem and the superficial veins of the cerebrum lead to larger vessels referred to as intracranial sinuses. These include the superior and inferior sagittal sinuses, straight sinus, cavernous sinuses, left and right sinuses, the petrosal sinuses, and the occipital sinuses. Ultimately, sinuses will lead back to either the inferior jugular vein or vertebral vein. Most of the veins on the superior surface of the cerebrum flow into the largest of the sinuses, the superior sagittal sinus. It is located midsagittally between the meningeal and periosteal layers of the dura mater within the falx cerebri and, at first glance in images or models, can be mistaken for the subarachnoid space. Most reabsorption of cerebrospinal fluid occurs via the chorionic villi (arachnoid granulations) into the superior sagittal sinus. Blood from most of the smaller vessels originating from the inferior cerebral veins flows into the great cerebral vein and into the straight sinus. Other cerebral veins and those from the eye socket flow into the cavernous sinus, which flows into the petrosal sinus and then into the internal jugular vein. The occipital sinus, sagittal sinus, and straight sinuses all flow into the left and right transverse sinuses near the lambdoid suture. The transverse sinuses in turn flow into the sigmoid sinuses that pass through the jugular foramen and into the internal jugular vein. The internal jugular vein flows parallel to the common carotid artery and is more or less its counterpart. It empties into the brachiocephalic vein. The veins draining the cervical vertebrae and the posterior surface of the skull, including some blood from the occipital sinus, flow into the vertebral veins. These parallel the vertebral arteries and travel through the transverse foramina of the cervical vertebrae. The vertebral veins also flow into the brachiocephalic veins. Table 20.13 summarizes the major... Choices: - Maxillary sinus - Sphenoid sinus - Frontal sinus - superior sagittal sinus A:
A: superior sagittal sinus

Q: Q: What is the term for the use of radioactive decay to estimate the ages of fossils and rock? Read this paragraph and choose the correct option from the provided answers: Radioactive dating is the use of radioactive decay to estimate the ages of fossils and rocks. An example is carbon-14 dating. Choices: - isotope test - microwave theory - radioactive illustrating - radioactive dating A:
A: radioactive dating

Q: Q: When the oval window vibrates, it causes what else to vibrate as well? Read this paragraph and choose the correct option from the provided answers: The stirrup in the middle ear passes the amplified sound waves to the inner ear through the oval window. When the oval window vibrates, it causes the cochlea to vibrate as well. The cochlea is a shell-like structure that is full of fluid and lined with nerve cells called hair cells. Each hair cell has many tiny "hairs," as you can see in the magnified image below . When the cochlea vibrates, it causes waves in the fluid inside. The waves bend the "hairs" on the hair cells, and this triggers electrical impulses. The electrical impulses travel to the brain through nerves. Only after the nerve impulses reach the brain do we hear the sound. Choices: - cilia - timpani - hammer and anvil - the cochlea A:
A: the cochlea

Q: Q: What is the most electron-pair bonds a nitrogen atom can participate in? Read this paragraph and choose the correct option from the provided answers: Reactions and Compounds of Nitrogen Like carbon, nitrogen has four valence orbitals (one 2s and three 2p), so it can participate in at most four electron-pair bonds by using sp3 hybrid orbitals. Unlike carbon, however, nitrogen does not form long chains because of repulsive interactions between lone pairs of electrons on adjacent atoms. These interactions become important at the shorter internuclear distances encountered with the smaller, second-period elements of groups 15, 16, and 17. (For more information on internuclear distance, see Chapter 7 "The Periodic Table and Periodic Trends", Section 7.2 "Sizes of Atoms and Ions" and Chapter 8 "Ionic versus Covalent Bonding", Section 8.2 "Ionic Bonding". ) Stable compounds with NN bonds are limited to chains of no more than three N atoms, such as the azide ion (N 3). Nitrogen is the only pnicogen that normally forms multiple bonds with itself and other second-period elements, using overlap of adjacent np orbitals. Thus the stable form of elemental nitrogen is N 2, whose NN bond is so strong (DNN = 942 kJ/mol) compared with the NN and N=N bonds (DNN = 167 kJ/mol; DN=N = 418 kJ/mol) that all compounds containing NN and N=N bonds are thermodynamically unstable with respect to the formation of N2. In fact, the formation of the NN bond is so thermodynamically favored that virtually all compounds containing NN bonds are potentially explosive. Again in contrast to carbon, nitrogen undergoes only two important chemical reactions at room temperature: it reacts with metallic lithium to form lithium nitride, and it is reduced to ammonia by certain microorganisms. (For more information lithium, seeChapter 21 "Periodic Trends and the ". ) At higher temperatures, however, N2 reacts with more electropositive elements, such as those in group 13, to give binary nitrides, which range from covalent to ionic in character. Like the corresponding compounds of carbon, binary compounds of nitrogen with oxygen, hydrogen, or other nonmetals are usually covalent molecular... Choices: - seven - five - three - four A:
A: four