ATI TEAS Practice Science Test

Correct Answer: A

Rationale: The correct answer is A: Adenine. Adenine forms a complementary base pair with cytosine through hydrogen bonding in DNA. This pairing is essential for maintaining the structure and stability of the DNA double helix. Adenine and cytosine form two hydrogen bonds between them. Choices B, C, and D are incorrect because cytosine does not bind with itself (B), guanine (C), or thymine (D) in DNA. Thymine pairs with adenine, while guanine pairs with cytosine. Therefore, the correct base that binds with cytosine is adenine.

Correct Answer: C

Rationale: The correct order of airflow in the lungs is Trachea, Bronchi, Bronchioles, Alveoli (Option C). The rationale is: 1. Air enters through the trachea. 2. Trachea branches into bronchi. 3. Bronchi further divide into bronchioles. 4. Bronchioles lead to the alveoli where gas exchange occurs. Summary: Option A is incorrect as it starts with bronchi before the trachea. Option B is incorrect as it reverses the order of bronchioles and bronchi. Option D is incorrect as it places alveoli before bronchioles and trachea before bronchi.

Correct Answer: A

Rationale: During Prophase I of meiosis, chiasmata structures form as homologous chromosomes exchange genetic material through crossing over. This occurs after homologous chromosomes pair up during synapsis. Chiasmata play a crucial role in genetic diversity. In contrast, Prophase II is focused on preparing the cells for division, and chiasmata formation does not occur during this phase. Metaphase I is characterized by the alignment of homologous chromosomes at the metaphase plate, while Metaphase II involves the alignment of sister chromatids. Therefore, the correct answer is A: Prophase I, as it is the specific phase where chiasmata formation takes place.

Correct Answer: B

Rationale: The correct answer is B: Ribcage. The ribcage is a bony structure that surrounds and protects the lungs. It consists of ribs, sternum, and thoracic vertebrae, forming a protective cage around the vital organs in the thoracic cavity. The ribs provide a barrier against external forces and help maintain the shape and integrity of the lungs. The other choices are incorrect because the femur is a bone in the leg, the scapula is a bone in the shoulder, and the skull protects the brain, not the lungs.

Correct Answer: A

Rationale: The correct answer is A: Adenine. Adenine forms a complementary base pair with cytosine through hydrogen bonding in DNA. This pairing is essential for maintaining the structure and stability of the DNA double helix. Adenine and cytosine form two hydrogen bonds between them. Choices B, C, and D are incorrect because cytosine does not bind with itself (B), guanine (C), or thymine (D) in DNA. Thymine pairs with adenine, while guanine pairs with cytosine. Therefore, the correct base that binds with cytosine is adenine.