81.

Beta ($\mathrm{\beta }$) diversity refers to diversity

• within a community

• between communities

• between two eco zones

• within a population

Which one of the following antibiotics kills bacterial cells by inhibiting the polymerisation of peptidoglycan?

• Aminoglycosides

• Fluoroquinolones

• Quinines

• Penicillins

Indicate the correct sequence during spermatogenesis.

• Spermatozoa $\to$ spermatogonia $\to$ spermatid  $\to$spermatocyte

• Spermatogonia $\to$ spermatocyte $\to$ spermatid $\to$ spermatozoa

• Spermatid $\to$ spermatocyte $\to$ spermatozoa  $\to$spermatogonia

• Spermatocyte $\to$ spermatozoa $\to$ spermatid  $\to$spermatogonia

Egg in female gametophyte is accompanied by

• antipodal cells

• synergids

• definitive nucleus

• tube nucleus

Malacophily is the pollination by

• insects

• birds

• snails

• mammals

Which one of the following organisms is not used as a biocontrol agent?

• Bacillus sphaericus

• Trichoderma viride

• Bacillus thuringiensis

• Bacillus subtilis

Which one of the following statements is relevant to sex linked characters?

• They always follow criss-cross inheritance

• They do not follow criss-cross inheritance

• They are mostly present on Y-chromosome

• They are only present on X-chromosome

Which one of the following insecticides is of plant origin?

• Ecdysone

• Rotenone

• Parathion

• Malathion

The resting state of reptiles in winter is

• hibernation

• aestivation

• diapause

• moulting

Archaeopteryx is a connecting link between

• pisces and amphibians

• amphibians and reptiles

• reptiles and birds

• birds and mammals