21.

Axile placentation is present in

• Dianthus

• Lemon

• Pea

• Pea

Which of the following are not membrane bound?

• Vacuoles

• Ribosomes

• Lysosomes

• Lysosomes

The body cells in cockroach discharge their nitrogenous waste in the haemolymph mainly in the form of 

• ammonia

• potassium urate

• urea

• urea

Which of the following biomolecules does have a phosphodiester bond?

• Fatty acids in a diglyceride

• Monosaccharides in a polysaccharide

• Amino acids in a polypeptide

• Amino acids in a polypeptide

Arrange the following events of meiosis in correct sequence:
(a) Crossing over
(b) Synapsis
(c) Terminalisation of chiasmata
(d) Disappearance of nucleolus

• (b), (a,) (d), (c)

• (b), (a) (c), (d)

• (a), (b) (c), (d)

• (a), (b) (c), (d)

Root pressure develops due to

• active absorption

• low osmotic potential in soil

• passive absorption

• passive absorption

Which one of the following animals has two separate circulatory pathways?

• Frog

• Lizard

• Whale

• Whale

The structures that help some bacteria to attach to rocks and/or host tissues are

• Rhizoids

• Fimbriae

• mesosomes

• mesosomes

Body having meshwork of cells, internal cavities lined with food filtering flagellated cells and indirect development are the characteristic of phylum

• Coelenterate

• Porifera

• Mollusca

• Mollusca

The oxygen evolved during photosynthesis comes from water molecules. Which one of the following pairs of elements is involved in this reaction?

• Manganese and Chlorine

• Manganese and Potassium

• Magnesium and Molybdenum

• Magnesium and Molybdenum