Ecosystem — BIOLOGY STD 12 Science — Question

Write one difference between binary fission and budding.

During reproduction, the chromosome number (2n) reduces to half (n) in the gametes and again resume the original number (2n) in the offspring, what are the processes through which these events take place?

“Pollen grains in wheat are shed at 3-celled stage while in peas they are shed at 2-celled stage.” Explain. Where are germ pores present in a pollen grain?

What are the different levels of biodiversity?

Explain the interdependence of producers and consumers.

A and B are the two different cloning vectors in two different bacterial colonies cultured in chromogenic substrate, Bacterial colonies with cloning vector A were colourless, whereas those with B were bluecoloured. Explain giving reasons the cause of the difference in colour that appeared.

Justify the need for signing of Montreal Protocol by the participating nations.

Name the hormonal composition of the oral contraceptive used by human females. Explain how does it act as a contraceptive.

Write down the possible levels of regulation of gene expression in eukaryotes.

Give two reasons for keeping beehives in crop fields during flowering periods