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WAEC GCE 2020: Jan/Feb Biology { Obj & Essay } Answers.


WAEC GCE 2020 BIOLOGY { OBJ & ESSAY } ANSWERSBY EXAMCAMP TEAM


BIOLOGY OBJ:

1-10: DABCADACDC
11-20: DCCBADCCDC
21-30: BCABBABAAB
31-40: AABDDCDBCC
41-50: BCCBDAACAC

ESSAY ANSWERS

(1a)
In Tabular Form

-Hormonal coordination:
(i) Transmission is chemical
(ii) Slow transmission
(iii) Response is wide spread
(iv) Target organs receive response
(v) Long lasting response

-Nervous coordination:
(i) Transmission is electrical and chemical
(ii) Rapid transmission
(iii) Response localized
(iv) Effector organs receive response
(v) Short-lived response

(1bi)
(i) It increases oestradiol production.
(ii) Essential in pubertal development.

(1bii)
(i) It regulates and balances the amount of water in the blood.
(ii) It helps to control blood pressure by acting on the kidneys and the blood vessels.

(1biii)
[pick any 3]
(i) It stimulates the liver to convert glycogen to Sugar thereby increasing the blood sugar level.
(ii) It increases the rate of Heartbeat and breathing.
(iii) it increases the muscle tone for higher work rate.
(iv) it prepares the body for emergency.
(v) it is associated with fear or anxiety and brings about shivering when the animal feels cold.

(1c)
The hormone is degraded or destroyed after performing its functions

(1d)
Auxins help in bending the shoot upwards and downwards due to gravity which shows negative geotropism and positive geotropism.
If a shoot is placed horizontally in the absence of light, auxins accumulate on the lower side of the shoot, due to gravity; the shoot bends upwards whereas if a root is placed horizontally in the absence of light,auxins accumulate on the lower side of the shoot, due to gravity; the shoot bends downwards.

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(3a)
(i) Presence of succulent stem to store water
(ii) Presence of pneumatophores or breathing roots for breathing atmospheric air
(iii) presence of stilt roots for anchorage
(iv) Viviparous seedling to ensure their survival/continuity

(3bi)
Secondary succession is the series of community changes which take place on a previously colonized, but disturbed or damaged habitat.

(3bii)
(i) Soil quality
(ii) Water
(iii) Climate

(3biii)
As a pond develops seeds are flown in by birds and land animals come to inhabit the pond. These are the pond pioneers.
As more creatures arrive the debris on the bottom increases. Pondweed, and other submergent vegetation, appears and soon grow all along the bottom.
Emergent plants have roots under water while part of their bodies resides above the water line. Emergents then appear on the edges of the pond. Over time, sometimes hundreds of years, as ponds plants grow, die and decompose, layers of debris build up.

(3c)
(i) Sickle cell anemia
(ii) Color-blindness
(iii) Diabetes
(iv) cystic fibrosis

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(5a)
(i)supply of blood
(ii)macrophages
(iii)dendritic cells
(iv)lymph vessels
(v)nerve endings

(5b)
(i)Decay is the process of breaking down complex organic matter into simple substances by microorganisms.
This process allows the recycling of organic substances
(ii)Digestion is the method of breaking down complex organic matter into simple compounds by enzymes, to be absorbed by the body. This is usually converted into energy.

(5c)
(i)The different ways that animals and plants are interdependent in an ecosystem because they depend on each other for basic survival needs like food
(ii)For Protection
(iii)For shelter and propagation.
(iv)plants also benefit from animals in that animal can aid in seed dispersal ensuring the survival of plants in other regions of an ecosystem.

(5di)
(i)Density-dependent regulation can be affected by factors that affect birth Rates.
(ii)And Affect death rates such as competition and predation

(5dii)
(i)Density-independent regulation can be affected by factors that affect birth and death rates such as abiotic factors
(ii)environmental factors, i.e. severe weather and conditions such as fire.

(5e)
(i)benefit skin health
(ii)benefit immune health.

(5f)
(i)physical adaptation
(ii)structural Adaptation
(iii)the body works in circulating and respiration

(5g)
(i)Monitor health status to identify and solve community health problems.
(ii)Diagnose and investigate health problems and health hazards in the community.
(iii)Inform, educate, and empower people about health issues.
(iv)Mobilize community partnerships and action to identify and solve health problems.
(v)Develop policies and plans that support individual and community health efforts.
(vi)Enforce laws and regulations that protect health and ensure safety.

Updated: January 31, 2020 — 8:43 am

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