21.

The pivot joint between atlas and axis is a type of

• Fibrous joint

• Cartilaginous joint

• Synovial joint

• Synovial joint

Zygotic meiosis is characteristic of

• Marchantia

• Fucus

• Funaria

• Funaria

Frog's heart when taken out of the body continues to beat for some time
Select the best option from the following statements
(a) Frog is a poikilotherm
(b) Frog does not have any coronary circulation
(c) Heart is 'myogenic' in nature
(d) Heart is autoexcitable

• Only (c)

• Only (d)

• (a) & (b)

• (a) & (b)

Which statement is wrong for Krebs' cycle?

• There are three points in the cycle where NAD+ is reduced to NADH + H⁺

• There is one point in the cycle where FAD+ is reduced to FADH₂

• During conversion of succinyl CoA to succinic acid, a molecule of GTP is synthesised

• During conversion of succinyl CoA to succinic acid, a molecule of GTP is synthesised

In case of poriferans the spongocoel is lined with flagellated cells called :

• Ostia

• Oscula

• Choanocytes

• Choanocytes

Which of the following RNAs should be most abundant in animal cell?

• r-RNA

• t-RNA

• m-RNA

• m-RNA

Which among these is the correct combination of aquatic mammals?

• Seals, Dolphins, Sharks

• Dolphins, Seals, Trygon

• Whales, Dolphins, Seals

• Whales, Dolphins, Seals

With reference to factors affecting the rate of photosynthesis, which of the following statements is not correct?

• Light saturation for CO₂ fixation occurs at 10% of full sunlight

• Increasing atmospheric CO₂ concentration upto 0.05% can enhance CO₂ fixation rate

• C₃ plants responds to higher temperatures with enhanced photosynthesis while C₄ plants have much lower temperature optimum

• C₃ plants responds to higher temperatures with enhanced photosynthesis while C₄ plants have much lower temperature optimum

Out of 'X' pairs of ribs in humans only 'Y' pairs are true ribs. Select the option that correctly represents values of X and Y and provides their explanation :

• X = 12, Y = 7
  True ribs are attached dorsally to vertebral column and ventrally to the sternum

• X = 12, Y = 5
  True ribs are attached dorsally to vertebral column and sternum on the two ends

• X = 24, Y = 7
  True ribs are dorsally attached to vertebral column but are free onventral side

• X = 24, Y = 7
  True ribs are dorsally attached to vertebral column but are free onventral side

Lungs are made up of air-filled sacs the alveoli. They do not collapse even after forceful expiration, because of :

• Residual Volume

• Inspiratory Reserve Volume

• Tidal Volume

• Tidal Volume