ati teas 7 science

Correct Answer: A

Rationale: The correct answer is A: Neuron. Neurons are the fundamental unit of the nervous system because they are specialized cells that transmit information through electrical and chemical signals. Neurons have a unique structure with dendrites, cell body, and axon, allowing them to receive, process, and transmit signals. Nerves (B) are bundles of neurons, ganglia (C) are clusters of neuron cell bodies, and neuroglia (D) are support cells in the nervous system. Neurons are the primary functional unit responsible for communication in the nervous system.

Correct Answer: B

Rationale: The correct answer is B: Identify the group number, which often indicates the typical ionic charge. Rationale: Elements in the same group on the periodic table have similar chemical properties, including their tendency to gain or lose electrons to form ions. The group number corresponds to the number of valence electrons an element has, which determines its typical ionic charge. For example, Group 1 elements tend to lose 1 electron to form a +1 ion, Group 2 elements lose 2 electrons to form a +2 ion, and so on. This pattern helps predict the charge of an ion formed by an element based on its position on the periodic table. Summary: A: Looking for elements with similar atomic weights does not directly relate to predicting the charge of an ion based on the periodic table. C: Identifying the period number does not provide information about the typical ionic charge of an element. D: Analyzing the element's position within the group is important, but the group

Correct Answer: A

Rationale: The correct arrangement of the small intestine segments is Duodenum, Jejunum, Ileum. The duodenum is the first segment where digestion occurs. The jejunum is the middle segment responsible for absorption, followed by the ileum for further absorption and passage of undigested material to the large intestine. Option A is correct as it follows the natural anatomical order and functional progression of the small intestine segments. Options B and C are incorrect as they incorrectly order the segments. Option D is also incorrect as there is a correct arrangement.

Correct Answer: C

Rationale: The correct answer is C: GABA. GABA is an inhibitory neurotransmitter that slows down neuron activity by binding to GABA receptors, leading to hyperpolarization of the neuron and reducing the likelihood of firing an action potential. This process helps to prevent overexcitation in the nervous system. A: Acetylcholine is primarily an excitatory neurotransmitter involved in muscle control and cognitive function. B: Dopamine plays a role in reward-motivated behavior and movement, but it is not primarily responsible for slowing down neuron activity. D: Serotonin is involved in regulating mood, appetite, and sleep, but it does not directly slow down neuron activity to prevent overexcitation.

Correct Answer: A

Rationale: The correct answer is A: Femur (thigh bone). The femur is the largest bone in the human body, providing structural support and mobility for the lower body. It is located in the thigh region and is crucial for walking, running, and overall movement. The other choices, B: Tibia, C: Humerus, and D: Scapula, are all significant bones in the body, but they are not as large as the femur. The tibia is the second largest bone but is smaller than the femur. The humerus is in the upper arm, and the scapula is in the shoulder, so they are not as large as the femur which is in the lower body and bears more weight.