Round 2: Biology (for only PM) grade 12

Which statement is CORRECT for homeostasis?

• It keeps the internal environment in a fixed state

• It keeps the internal fluctuations in a narrow range

• It keeps the external environment in a narrow range

• It does not maintain the level of hormones in the body

The inner renal medulla is highly concentrated as compared to the renal cortex due to the following, EXCEPT

• counter-current multiplier

• presence of urea in the medulla

• active pumping of Na ions into kidney interstituim

• active pumping of Na ions into blood stream in cortex

The head of femer articulates which bone of the pelvic girdle?

• Ileum

• Sacrum

• Ischium

• Acetabulum

Which one of the following is a function of Osteoclasts?

• Bone resorption

• Add calcium to bone

• Produce bone matrix

• Make bones stronger

The unmineralized ground substance of bone is formed by

• Osteocytes

• Osteoblasts

• Osteoclasts

• Chrondrocytes

Over activity of parathormone causes?

• Gall stones

• Kidney stone

• Muscular tetany

• Muscular dystrophy

Epilepsy is characterized by excessive rapid electrical discharges in the

• gray matter of brain

• white matter of brain

• symphatheic nerves

• parasymphathetic nerves

Juxtamedullary nephrone is the characteristics of

• fish

• frog

• snake

• kangaroo rat

The total number of vertebrae in the neck of giraffe is

• 5 vertebrae

• 7 vertebrae

• 9 vertebrae

• 11 vertebrae

10. Rodents respond to alarm calls by others in their group, if these calls are continued and no danger is conformed, further calls may be ignored. This is an example of

• Conditioned reflex type I

• Conditioned reflex type II

• Insight learning

• Habituation