WAEC BIOLOGY ANSWERS 2021
Here is the waec biology answers for 2021. We will post the waec biology answers for 2021 right here.
(ii) Red blood cell
(iii) White blood cell
(ii) White blood cells
(iii) Red blood cells
(v) Red blood cells
(vii) White blood cells
(i) Amino acids
(iii) Mineral salts and water
(iii) Blood clots
Disease of the blood is dangerous because it can lead to other issues and consequently death.
Dentition refer to the development of teeth and their arrangements in the mouth of animals
The tooth consists of three main portions namely ;The crown,neck and root. The crown is above the gum covered with a white hard substance called enamel. The short neck is covered with gum. The root is embedded in the jaw bone by a substance called cement or cementum
=ONE BODY PARTS THAT MAKES ANIMAL ENDANGERED BY HUMAN ACTIVITIES=
(i) Overgrazing; The activity of Overgrazing leads to the extraction of grasses which invariably leads to erosion-wasting away of the soil surface
(ii) Poaching; Poaching which is damage by the soil and grass also leads to gulley erosion
(i)The establishment of forestry departments and establishment of environment Protection agency to improve the situation.
(ii)the role of creation of Parks and Games Reserves/any correctly named example.
(iii)the role of conservation education carried out through tree planting/ campaigns against bush burning/ tree.
(iv)the role of preserve/maintain plants and animals in their natural environment
Biofuel, any fuel that is derived from biomass—that is, plant or algae material or animal waste. Since such feedstock material can be replenished readily, biofuel is considered to be a source of renewable energy, unlike fossil fuels such as petroleum, coal, and natural gas.
(i) Carbon cycle
(ii) Water cycle
(iii) Nitrogen cycle
(i) Photosynthesis, decomposition, respiration
(ii) Condensation, transpiration evaporation
(iii) Nitrification, ammonification, denitrification
Irritability can be defined A the response to external stimulus. It is one of the characteristics of living organisms which they used in relating to these environment
(i) Euglena moving towards light
(ii) Opening and closing of minosa plant leaves
(iii) Mosquito avoiding repellants
(iv) Earthworm moving away from light
(v) Sperm cell moving towards chemical substances of an ovum
(vi) Four o’clock plant opening at 4:00pm
(vii) Shoot of bean seedlings growing towards sunlight
=TYPES OF RESPONSE=
(iii) Negative chemotaxis
(v) Positive chemotaxis
(vii) Positive Phototropic
(i) Dragon flies
(iii) Northern elephant
(ii) Poultry birds
2b) A tooth consists of enamel, dentin, cementum and pulp tissue. The portion of a tooth exposed to the oral cavity is known as the dental crown, and the portion below the dental crown is known as the tooth root. The dental pulp cavity exists in the center of the tooth, through which the dental pulp, called the nerve, runs. In order to receive an impact on the tooth and to absorb and alleviate the force on the jaw, the surface of the tooth root area (cementum) and the alveolar bone are connected by a fibrous tissue called the periodontal ligament. The tooth is supported by the tissue consisting of the alveolar bone, gums and the periodontal ligament.
Enamel: The hardest bodily tissue covering the surface of the dental crown. It is as hard as crystal (7 on the Mohs scale of mineral hardness).
Dentin: The tissue that forms the tooth from the dental crown to the tooth root, situated inside the enamel and cementum. It is softer than the enamel. A small tube filled with tissue fluid, called the dentinal tubule, runs inside the dentin.
Cementum: The tissue covering the surface of the tooth root. It connects the alveolar bone with the tooth by the periodontal ligament. Its hardness is similar to bone.
Dental pulp: The tissue is called the nerve. Blood vessels and the lymph vessels, as well as nerve fibers, are located in the dental pulp, supplying nutrients to the dentin.
Periodontal ligament: Tissue consisting mainly of the fibrous tissue that connects the tooth root and the alveolar bone. It prevents force applied to the tooth from being directly imposed on the alveolar bone while chewing food.
Alveolar bone: The jaw bone supporting the tooth; the tooth is planted into this bone. When a large part of the alveolar bone is destroyed by periodontal disease or other causes, the tooth becomes loose.
Gingiva: The soft tissue covering the alveolar bone. It is generally called “gum”.
Gingival sulcus: The small space between the tooth and the gums. Even people with healthy teeth usually have a depth of 1 to 2 mm in this space. When this space deepens due to inflammation, it is called the periodontal pocket or gingival pocket.
Many blood diseases and disorders are caused by genes. Other causes include other diseases, side effects of medicines, and a lack of certain nutrients in your diet. Common blood disorders include anemia and bleeding disorders such as hemophilia.
5a) Guttation is the loss of water in the form of water droplets from hydathodes (small pores) on the leaf margin of a small herbacious plant.
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