TEAS 7 science practice

Correct Answer: D

Rationale: The correct answer is D: Mouth. The mouth is responsible for the mechanical breakdown of food through chewing and mixing with saliva. This process is essential for breaking down food into smaller, more digestible pieces before swallowing. The esophagus (choice A) is a muscular tube that transports food from the mouth to the stomach and does not participate in the mechanical breakdown of food. The stomach (choice B) primarily functions to further break down food using acids and enzymes, rather than mechanical means. The small intestine (choice C) is responsible for absorbing nutrients from the digested food, not for the mechanical breakdown of food.

Correct Answer: C

Rationale: Synergistic muscles are groups of muscles that work together in a coordinated manner to produce a specific movement. They synchronize their actions to achieve a common goal efficiently. In contrast, antagonistic muscles work in opposing directions, and agonistic muscles, also known as prime movers, are responsible for initiating a movement. Flexors and extensors represent muscles that perform contrasting actions around a joint, such as bending and straightening. Therefore, the correct answer is C - 'Synergistic muscles,' as they collaborate to facilitate a specific movement, unlike the other choices which describe different muscle functions within the body.

Correct Answer: B

Rationale: The correct answer is B. Alpha decay involves the release of a helium nucleus, which consists of two protons and two neutrons. In contrast, beta decay releases an electron (beta-minus decay) or a positron (beta-plus decay). This significant distinction in the particles emitted during the decay processes distinguishes alpha decay from beta decay. Choice A is incorrect because alpha and beta decay release different types of particles. Choice C is incorrect as beta decay is more common than alpha decay in many cases. Choice D is incorrect as it does not specifically address the particles released during alpha and beta decay.

Correct Answer: D

Rationale: The waste product of protein digestion is ammonia. Protein digestion breaks down proteins into amino acids, and during this process, ammonia is produced. Ammonia is toxic and needs to be converted into urea in the liver for excretion via urine. Glucose is a product of carbohydrate digestion, amino acids are building blocks of proteins, and fatty acids are the end products of fat digestion. Therefore, the correct answer is ammonia.

Correct Answer: B

Rationale: Acetylcholine is the neurotransmitter responsible for stimulating muscle contraction at the neuromuscular junction. When an action potential reaches the end of a motor neuron, acetylcholine is released into the synaptic cleft and binds to receptors on the muscle cell membrane, leading to muscle contraction. Dopamine, serotonin, and norepinephrine are neurotransmitters that have different functions in the nervous system and are not directly involved in stimulating muscle contraction. Dopamine is involved in reward and pleasure pathways, serotonin regulates mood and behavior, and norepinephrine is involved in the 'fight or flight' response.