ati teas 7 science

Correct Answer: B

Rationale: The correct answer is B: Nucleotide. Nucleotides are the building blocks of DNA, consisting of a sugar molecule, a phosphate group, and a nitrogenous base. They are linked together in a specific sequence to form the DNA molecule's double helix structure. Amino acids (choice A) are the building blocks of proteins, not DNA. Phosphate groups (choice C) are components of nucleotides but are not the sole building blocks of DNA. Fatty acids (choice D) are not involved in the structure of DNA at all. Therefore, the correct answer is nucleotide as it accurately represents the basic components that make up DNA.

Correct Answer: A

Rationale: The correct answer is A: Solid. Solids have both a definite volume and a definite shape because the particles are tightly packed and vibrate in fixed positions. This leads to a rigid structure and minimal movement, maintaining the shape and volume. In contrast, liquids (B) have a definite volume but take the shape of their container, gases (C) have neither a definite shape nor volume as they expand to fill the container, and plasmas (D) have no definite shape or volume due to their high energy state.

Correct Answer: B

Rationale: In mitosis, sister chromatids are separated and move to opposite poles during Anaphase. This is when the spindle fibers shorten, pulling chromatids apart. Metaphase is when chromosomes align in the middle. Telophase is when the nuclear envelope reforms. Cytokinesis is the division of the cytoplasm. Therefore, B is correct as it specifically describes the phase where sister chromatids separate and move to opposite poles.

Correct Answer: B

Rationale: The primary function of red blood cells is to transport oxygen. They contain hemoglobin, which binds to oxygen in the lungs and delivers it to tissues throughout the body. This process is essential for cellular respiration and energy production. Choice A is incorrect because while red blood cells do transport nutrients, their main role is oxygen transport. Choice C is incorrect because fighting infection is primarily the role of white blood cells. Choice D is incorrect as red blood cells do not produce antibodies; that is the function of specialized white blood cells called B cells.

Correct Answer: D

Rationale: Step 1: Given the object is moving in a circle at a constant speed, it experiences centripetal acceleration towards the center. Step 2: According to Newton's first law, an object in motion stays in motion unless acted upon by a net force. Step 3: The only force causing the object to change its direction is the centripetal force. Step 4: Therefore, the net force acting on the object is required to continuously change its direction. Summary: Choice A is incorrect because the net force is not always present. Choice B is incorrect as centripetal force acts on the object. Choice C is incorrect as speed can be constant in circular motion.