NECO GCE 2025 Biology Answers

NECO GCE 2025 BIOLOGY ANSWERS

BIOLOGY OBJ
1-10: ACAABADBDB
11-20: EBBEEEBCCA
21-30: BBEBBEBDDB
31-40: CEABCCACEB
41-50: BEABCDBDBC
51-60: CACAEEBACA

INSTRUCTIONS: ANSWER THREE(3) QUESTIONS ONLY

(1ai)
(i) Pituitary gland
(ii) Thyroid gland
(iii) Adrenal glands
(iv) Pancreas

(1aii)
(i) High salinity causes dehydration of body tissues as water moves out of the organisms by osmosis.
(ii) It leads to osmotic stress, making it difficult for many organisms to maintain water and salt balance.
(iii) Many non-adapted organisms may experience reduced growth or death because their enzymes and metabolic processes become disrupted.
(iv) High salinity limits species diversity, allowing only salt-tolerant (halophytic or euryhaline) organisms to survive.

(1aiii)
(i) Nitrogen (N)
(ii) Phosphorus (P)

(1bi)
[DRAW THE DIAGRAM]

(1bii)
(i) A semipermeable membrane.
(ii) A difference in water concentration on both sides of the membrane.
(iii) A difference in solute concentration between the two solutions.
(iv) The presence of water molecules as the moving particles.

(2ai)
[TABULATE]

=MONOCOT PLANTS=
(i) Have one seed leaf (cotyledon)
(ii) Leaves have parallel venation
(iii) Vascular bundles are scattered in the stem

=DICOT PLANTS=
(i) Have two seed leaves (cotyledons)
(ii) Leaves have net/reticulate venation
(iii) Vascular bundles are arranged in a ring

(2aii)
(i) It has high rainfall throughout the year.
(ii) It has high temperature and high humidity.
(iii) It contains dense vegetation with tall evergreen trees and many layers (canopy).

(2bi)
(i) Water in the soil enters the root hairs by osmosis because the cell sap of root hairs is more concentrated than the surrounding soil water.
(ii) Mineral salts dissolved in soil water enter the root hairs by diffusion or active transport depending on their concentration.
(iii) Water moves from the root hair cells into the cortex cells by osmosis, passing from cell to cell across the root tissues.
(iv) From the cortex, water enters the xylem vessels in the root.
(v) The xylem vessels conduct water upward through the stem by transpiration pull, root pressure, and capillarity.
(vi) Water finally reaches the leaves, where it is used for photosynthesis or lost through transpiration.

(2bii)
(i) Apple
(ii) Pineapple

(2biii)
(i) They help in growth and repair of body tissues.
(ii) They help in the formation of enzymes and hormones.
(iii) They provide the body with energy when fats and carbohydrates are insufficient.

(3ai)
(i) They have feathers covering their bodies.
(ii) They possess beaks without teeth.
(iii) Their forelimbs are modified into wings for flight (although not all birds fly).
(iv) They are warm-blooded (maintain constant body temperature).
(v) They lay hard-shelled eggs.

(3aii)
(i) Collenchyma
(ii) Sclerenchyma
(iii) Xylem
(iv) Phloem

(3aiii)
(i) Nephritis
(ii) Kidney stones

(3bi)
(i) During sexual intercourse, sperm cells are released into the vagina through ejaculation.
(ii) The sperm swim through the cervix and uterus toward the fallopian tube where the ovum is located.
(iii) At ovulation, a mature egg is released from the ovary into the fallopian tube.
(iv) Many sperm surround the egg, but only one sperm succeeds in penetrating the egg membrane.
(v) Once the head of one sperm enters the egg, a fertilisation membrane forms, preventing other sperm from entering.
(vi) The nucleus of the sperm fuses with the nucleus of the egg to form a zygote.
(vii) The zygote begins to divide and eventually moves to the uterus for implantation.

(3bii)
(i) It leads to destruction of habitats, causing loss of plants and displacement or death of animals.
(ii) It causes soil erosion and nutrient loss, reducing soil fertility and affecting plant growth.

(4ai)
(i) Detoxification: It removes and breaks down harmful substances such as drugs and poisons.
(ii) Bile production: It produces bile used in the emulsification of fats.
(iii) Storage of glycogen: It converts excess glucose to glycogen for storage and releases it when needed.
(iv) Protein metabolism: It deaminates excess amino acids and forms plasma proteins.
(v) Storage of vitamins and minerals: It stores vitamins A, D, B12, and minerals such as iron.

(4aii)
(i) Double circulation means blood passes through the heart twice in one complete circuit around the body.
(ii) The first circulation is the pulmonary circulation, where deoxygenated blood is pumped from the right ventricle to the lungs for oxygenation.
(iii) Oxygenated blood returns to the left atrium through the pulmonary veins.
(iv) The second circulation is the systemic circulation, where oxygenated blood is pumped from the left ventricle to all parts of the body.
(v) Deoxygenated blood returns to the right atrium, completing the cycle, ensuring efficient oxygen supply and high blood pressure in the systemic circuit.

(4bi)
[DRAW THE DIAGRAM]

(4bii)
(i) Piercing and sucking mouthparts for feeding on blood.
(ii) Light, narrow bodies and long legs that allow silent landing on hosts.
(iii) Anticoagulant saliva that prevents blood clotting and enables easy parasite transmission.
(iv) Nocturnal feeding habit, which allows them to bite hosts when they are inactive or asleep.