1. Which of the following is NOT a type of epithelium

A. Stratified squamous
B. Simple cuboidal
C. Stratified columnar
D. Stratified columnar

Correct answer: D

Rationale: The correct answer is D, 'Stratified columnar.' Epithelial tissues are classified based on their structure and function. Stratified squamous epithelium consists of multiple layers of flattened cells and is found in areas that need protection, like the skin. Simple cuboidal epithelium is a single layer of cube-shaped cells that function in secretion and absorption, commonly found in kidney tubules. Stratified columnar epithelium is a rare type with multiple layers of column-shaped cells, primarily found in the male urethra. Since 'Stratified columnar' is a valid type of epithelium, it is NOT the correct answer for this question.

2. Which hormone stimulates the release of calcium from bones and increases blood calcium levels?

A. Parathyroid hormone (PTH)
B. Calcitonin
C. Growth hormone
D. Testosterone

Correct answer: A

Rationale: The correct answer is A: Parathyroid hormone (PTH). PTH is produced by the parathyroid glands and plays a crucial role in regulating calcium levels in the blood. When blood calcium levels are low, PTH is released to stimulate the release of calcium from bones, increase calcium absorption in the intestines, and reduce calcium loss in the kidneys. This process helps to maintain the necessary balance of calcium in the body. Calcitonin, on the other hand, works in opposition to PTH by decreasing blood calcium levels. Growth hormone primarily stimulates growth and development of tissues, while testosterone is a male sex hormone and does not directly impact calcium regulation.

3. Which of the following phases of mitosis is characterized by the separation of sister chromatids and their movement to opposite poles?

A. Metaphase
B. Anaphase
C. Anaphase
D. Cytokinesis

Correct answer: B

Rationale: Rationale: During anaphase of mitosis, the sister chromatids, which are duplicated copies of a chromosome, separate and move towards opposite poles of the cell. This movement is facilitated by the shortening of microtubules attached to the chromatids. As a result, each pole of the cell receives a complete set of chromosomes, ensuring that the daughter cells produced after cell division will have the correct number of chromosomes. Metaphase is characterized by the alignment of chromosomes at the cell's equator, not their separation. Telophase is the phase following anaphase, where the separated chromatids reach the opposite poles and nuclear envelopes start to form around them. Cytokinesis is the final stage of cell division, where the cytoplasm is divided to form two separate daughter cells.

4. When ice melts, it undergoes aâ€¦

A. Chemical change
B. Physical change
C. Nuclear change
D. Radioactive decay

Correct answer: B

Rationale: Melting is a change in physical state, not a change in the chemical composition of the ice.

5. What is the term for a substance that can act as both a proton donor and a proton acceptor?

A. Acid
B. Base
C. Amphiprotic
D. Neutral

Correct answer: C

Rationale: Amphiprotic substances can act as both a proton donor and a proton acceptor. The other choices are specific to either acids or bases.

6. What are isotopes?

A. Atoms of the same element with different numbers of protons.
B. Atoms of the same element with different numbers of neutrons.
C. Atoms of different elements with the same number of protons.
D. Atoms of different elements with the same number of electrons.

Correct answer: B

Rationale: Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons. This means that isotopes have the same atomic number (Z) but different mass numbers (A). For example, carbon-12 (Â¹Â²C), carbon-13 (Â¹Â³C), and carbon-14 (Â¹â´C) are all isotopes of carbon. They all have six protons in their nuclei, but they have different numbers of neutrons: carbon-12 has six neutrons, carbon-13 has seven neutrons, and carbon-14 has eight neutrons.