JAMB Biology Past Questions & Answers - Page 81

401.

The damage to ozone layer is caused by

A.

Oxygen

B.

Nitrogen oxide

C.

Chlorofluorocarbons

D.

sulphur dioxide

Correct answer is C

Ozone sits in the upper atmosphere and absorbs ultraviolet radiaton, another type of solar energy that's harmful to humans, animals, and plants. CFCs and halons cause chemical reactions that break down ozone molecules, reducing ozone's ultraviolet radiation-absorbing capacity

Chlorofluorocarbons (CFCs) and other halogenated ozone depleting substances (ODS) are mainly responsible for man-made chemical ozone depletion.

402.

 Name the blood cells in which nucleus is absent

A.

Lymphocytes

B.

Blood Platelets

C.

Monocytes

D.

Eosinophil

Correct answer is B

Like red cells, platelets (thrombocytes) have no nucleus. However, unlike red cells that originate in the marrow as nucleated cells and lose their nucleus, platelets are produced by budding off from a giant multinucleated marrow cell called a megakaryocyte.

403.

Botany is also known as

A.

Phytology

B.

Phycology

C.

Pedology

D.

Plantophyta

Correct answer is A

Phytology is the branch of biology that studies plants.

404.

Etiolation is caused by the influence of

A.

Mineral Salts

B.

Water

C.

Carbondioxide

D.

Light

Correct answer is D

Etiolation is a process in flowering plants grown in the partial or complete absence of light. It is characterized by long, weak stems; smaller leaves due to longer internodes; and a pale yellow color.

405.

Examples of micronutrients include the following except

A.

Vitamin A

B.

Vitamin B6

C.

Biotin

D.

carbon

Correct answer is D

Carbon is a macronutrient.