All Free Biology MCQs with Answers

1061. Robert Hooke discovered_____________?

• A. Nucleus
• B. Mitochondria
• C. Cell
• D. DNA

Explanation: Robert Hooke examined a thin slice of cork in 1665 and observed many small box-like compartments, which he called cells. He did not discover the nucleus, mitochondria, or DNA, although these structures were identified later by other scientists. The most likely mistake is choosing the nucleus because it is a prominent cell structure.

1062. A group of similar cells that perform a specific function is:

• A. Organ
• B. Tissues
• C. Organelle
• D. Organ System

Explanation: A tissue is a group of similar cells organized to perform a particular function, such as muscle tissue or epithelial tissue. An organ is made from several tissue types, so choosing organ confuses the next level of biological organization with the level described. The correct term is tissue.

1063. Various tissue types combine to make up__________?

• A. Cells
• B. Organs
• C. Organ System
• D. Organelles

Explanation: Different tissues combine structurally and functionally to form an organ, such as the heart, stomach, or leaf. An organ system is formed when several organs work together, so it is a higher level of organization. The likely mistake is choosing organ system because the question mentions more than one tissue type.

1064. With different chemical arrangements and formation Of complex molecules, the life emerges on the level of the ?

• A. Cells
• B. Tissues
• C. Organs
• D. Organ System

Explanation: The cell is the first level of biological organization regarded as living because it can carry out essential life processes. Molecules and organelles contribute to life but cannot independently perform all cellular functions. Students may choose organelle because complex molecules form organelles, but organelles are below the cellular level.

1065. Human blood is an example of__________?

• A. Organelle
• B. Tissues
• C. Organic compound
• D. Inorganic compounds

Explanation: Blood is a connective tissue because it contains cells and a fluid extracellular matrix called plasma, and it transports materials throughout the body. It is not an organic compound or an inorganic compound, since it is a complete living tissue made of many substances and cells. Students may choose organic compound because blood contains organic molecules, but its classification is based on its organization as tissue.

1066. Ginger is a______?

• A. Leave
• B. Root
• C. Stem
• D. None of These

Explanation: Ginger is a rhizome, which is a modified underground stem containing nodes and buds that can produce new shoots. Students often choose root because ginger grows underground, but roots do not have stem nodes or buds like a rhizome.

1067. Feathered shank is only seen in the class of ____________?

• A. Asian class
• B. English class
• C. American class
• D. None

Explanation: Feathered shanks, in which feathers extend down the legs, are a characteristic feature associated with the Asiatic or Asian class of poultry. Students may choose the English class because poultry breeds are also grouped by origin, but feathered shanks are classically linked with the Asian class.

1068. Stoma, found in the epidermis of leaves closes when guard cells

• A. Gain Water
• B. Lose Water
• C. Exchange gas
• D. None of These

Explanation: Guard cells lose water, become flaccid and reduce the stomatal pore, causing the stoma to close. When guard cells gain water they become turgid and usually open the pore, so “gain water” is the likely distractor.

1069. Which of the following plant group first formed true leaves?

• A. Psilopsida
• B. Lycopsida
• C. Sphenopsida
• D. Pteropsida

Explanation: Lycopsida were the first vascular plant group to develop true leaves, called microphylls, which have a single unbranched vein. Psilopsida were traditionally described as leafless, while Sphenopsida and Pteropsida appeared later. Students may choose Pteropsida because their leaves are larger and more familiar, but they were not the first to form leaves.

1070. Bean shaped cells in plants are: _________?

• A. Mesophyll cells
• B. Xylem Cells
• C. Phloem Cells
• D. Guard Cells

Explanation: Guard cells are specialized bean-shaped cells that surround each stomatal pore and regulate gas exchange and water loss. Students may choose mesophyll cells because they are common leaf cells involved in photosynthesis, but their shape is not typically described as bean-shaped.