Nitrifying bacteria keep the soil fertile by
converting nitrate to nitrogen
converting ammonium salt to nitrate
converting atmospheric nitrogen to plant nitrogen
converting nitrate to nitrous oxide
converting atmospheric nitrogen to nitrates
Correct answer is B
Nitrifying bacteria are microorganisms that help to convert soil ammonium to nitrates, the form in which it is usable by the plants.
Which of the following is a characteristic of animal cell?
Presence of chloroplast
possession of cellulose cell-wall
absence of large vacuoles
presence of large vacuoles
presence of chromosome
Correct answer is C
Unlike the plant cell which possesses one or a few large vacuoles, the animal cell possesses vacuoles but they are smaller in size and plenty in quantity when compared to that of the plants.
1,2,3,4,5
1,2,4,5,3
3,4,5,2,1
5,4,1,3,2
5,4,3,1,2
Correct answer is D
Sexual reproduction in Spirogyra occurs by a process known as conjugation, in which cells of two filaments lying side by side are joined by outgrowths called conjugation tubes.
This allows the contents of one cell to completely pass into and fuse with the contents of the other. The resulting fused cell (zygote) becomes surrounded by a thick wall and overwinters, while the vegetative filaments die.
to remove excess water in plant
to absorb water from the atmosphere
for gaseous exchange
to absorb light
to store food
Correct answer is C
A lenticel is one of many raised pores in the stem of a woody plant that allows gas exchange between the atmosphere and the internal tissues.
when protein are broken down they provide
oxygen
carbonhydrate
energy
amino-acid
carbon dioxide
Correct answer is D
The end-product of the breakdown of protein is amino-acids and other simple products.