2020/2021 WAEC/NECO Answers: 2020 waec gce Biology answer

(1a) In Tabular Form 

- Hormonal -

(i)Transmission is chemical   

(ii)Slow transmission 

(iii)Response is wide spread

(iv) Target organs receive response

(v)Long lasting response

- Nervous-

(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.

 (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.

(3a)

(i) The roots of aquatic plants are shallow and spread out over a large area and serve as support

(ii) Aquatic plants have mechanism for maintaining a high osmotic concentration in their cell which is close to that of the water in their habitat

(iii) The  roots of mangrove plants have many devices for taking in atmospheric oxygen

(iv) The seeds of mangrove plant germinates while they are still on the parent tree

(3bi)

Secondary succession is one of the two types ecological succession of a plants life. As opposed to the first, primary succession, secondary succession is a process started by an event that reduces an.

(3bii)

(i)temperatures

(ii)water

(iii)nutrient availability

(3biii)

Once a pond is created, seeds are flown in by birds or deposited by mammals who visit the pond. These first seed plants are called pond pioneers.As established plants grow and die they sink to the bottom of the pond and helping to fill in the shallow water. In other words Eventually the pond’s emergent plants may cover the entire pond turning the pond into a soggy marsh. In time the soft, wet ground of the marsh will be overtaken by plants and dry out. When that happens it means the pond has succeeded into a field or meadow. As plant life & soil conditions change, the wildlife attracted to the area will change.

(3c) 

(i) Sickle cell anemia

(ii) Color-blindness

(iii) Diabetes 

(iv) cystic fibrosis

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