2017 WAEC *GCE* BIOLOGY ANSWERS
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1ai)
– white blood cells
– lipids
1aii).
– responsible for the removal of interstitial fluid from tissues
– It transports white blood cells to and from the lymph nodes into the bones
1bi).
– oxygen
– excretory products, such as carbon dioxide, urea, etc
– Hormones
1bii)
Plants absorb water from the soil through their root hairs which are surrounded by soil water in the soil. The soil water is a more dilute solution than the soil sap inside the root hair hence water molecules move from soil water into the root hairs by the process of osmosis. Mineral salts are absorbed through the cell membrane often from a zone of their low concentration in the soil to a zone of their higher concentration in the cells of the roots through active absorption.
1ci)
Placentation is the arrangement of ovules within an ovary. The part of the ovary where the ovules are attached is called a placenta.
1cii)
– Marginal placentation
– Parietal placentation
– Axile placentation
– Free central placentation
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3ai)
Community : is any naturally Occurring group of different organisms living together and interacting in the same environment.
3aii
Population: is defined as the total number of organisms of the same species living together in a given area
3aiii)
Ecologicalnide: Refers to the specific portion of a habit which is occupied by a particular organism
3b)
Because all living organism need energy and nutrient in an environment in other to sustrundipe
3ci)
– Lack of enough food
– out break of disease
– lack of money
3cii)
– Exposed the soil into erosion
– Cause loss of nutrient into the plant
– Cause low yield
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6a)
i)it has gills for gaseous exchange
ii)it has a long tail that facilitates its movement
iii)its sucker secretes sticky cement which aids attachment to water weeds
iv)it has mouth with horny jaw for feeding
6bi)
Irritability is the ability to be excited to a characteristic action or function by the application of some stimulus
Or
Irritability is the Abnormal sensitivity or excessive responsiveness, as of an organ or body part, to a stimulus.
6bii)
– Water
– Light
6ci) Tillage is the agricultural preparation of soil by mechanical agitation of various types, such as digging, stirring, and overturning. Examples of human-powered tilling methods using hand tools include shovelling, picking, mattock work, hoeing, and raking
6cii)
– it Destroy soil living organism
– it reduces soil fertility
– it causes soil erosion
6d) territoriality: this is the process in which male agama lizard prevent other males frm entering into it niche containing few female lizard, colour display: male agama lizard may bask in d sun so dat it reddish head will become more brigther in order to attract potential female lizard
6ei) Oviparity is the expulsion of undeveloped eggs rather than live young. The eggs may have been fertilized before release, as in birds and some reptiles, or are to be fertilized externally, as in amphibians and many lower forms. In general, the number of eggs produced by oviparous species greatly exceeds the number of offspring from species that bear live young, but the chances of survival are diminished because of the lack of maternal protection.
Or
Oviparity is the producing eggs that mature and hatch after being expelled from the body, as birds, most reptiles and fishes, and the monotremes.
6eii) Viviparity is the retention and growth of the fertilized egg within the maternal body until the young animal, as a larva or newborn, is capable of independent existence. The growing embryo derives continuous nourishment from the mother, usually through a placenta or similar structure.
6f)
Rhizobium turns the free Nitrogen in air into
– Ammonia
– Nitrate
Typed by Maradona
