Earthworms have no skeleton but during burrowing, the anterior end becomes turgid and acts as a hydraulic skeleton. It is due to

• Coelomic fluid

• blood

• gut peristalsis

• gut peristalsis

Cornea transplant in humans is almost never rejected. This is because

• its cells are least penetrable by bacteria

• It has no blood supply

• It is composed of enucleated cells

• It is composed of enucleated cells

The energy -releasing process in which the substrate is oxidised without an external electron acceptor called

• fermentation

• photorespiration

• aerobic respiration

• aerobic respiration

Select one of the following pairs of important features distinguishing Gnetum from Cycas and Pinus and showing affinities with angiosperms

• the absence of resin duct and leaf venation

• the presence of vessel elements and absence of archegonia

• perianth and two integuments

• perianth and two integuments

Thorn of Bougainvillea and tendril of Cucurbita are examples of 

• analogous organs

• homologous organs

• vestigial organs

• vestigial organs

In the light of recent classification of living organisms into three domains of life (bacteria, archaea and eukarya), which one of the following statement is true about archaea? 

• Archaea resemble eukarya in all respects

• Archaea have some novel features that are absent in other prokaryotes and eukaryotes

• Archaea completely differ from both prokaryotes and eukaryotes

• Archaea completely differ from both prokaryotes and eukaryotes

Thermococcus, Methanococcus and Methanobacterium emplify

• archaebacteria that contain protein homologous to eukaryotic core histones

• archaebacteria that lack any histones resembling those found in eukaryotes but DNA is negatively supercoiled

• bacteria whose DNA is relaxed or positively supercoiled but which have cytoskeleton as well as mitochondria

• bacteria whose DNA is relaxed or positively supercoiled but which have cytoskeleton as well as mitochondria

A competitive inhibitor of succinic dehydrogenase is 

• malonate

• oxaloacetate

• alpha-ketoglutarate

• alpha-ketoglutarate

39.

Vacuole in a plant cell

• is membrane-bound and contains storage

• is membrane-bound and contains water and excretory substances

• lacks membrane and contains air

• lacks membrane and contains air

Which one of the following items gives its correct total number? 

• Floating ribs in humans - 4 

• Amino acids found in proteins - 16

• Types of diabetes - 3 

• Types of diabetes - 3