Cut surfaces of fruit and vegetables often become dark because
dirty knife makes it dark
oxidation of tannic acid in the presence of trace of iron from the knife makes it dark
dust of the air makes it dark
none of the above.
B.
oxidation of tannic acid in the presence of trace of iron from the knife makes it dark
When fresh fruits and vegetables are peeled or cut open, the enzyme called polyphenol oxidase (also called tyrosinase) contained in the cells is exposed to and reacts with the oxygen in the air. The reaction that occurs, which is called oxidation, is what turns the fruits and vegetables brown.
The branched sclereids present in hydrophytes are
osteosclereids
trichosclereids
macrosclereids
astrosclereids
Cleistogamy is leading over anthesis because
pollination agent is not required
it assures heterozygosity
it favours insect pollination
it allows xenogamy
Assertion : On plotting the length of the root against time, a linear curve is obtained.
Reason : An elongating rout exemplifies arithmetic growth.
If both assertion and reason are true and reason is the correct explanation of assertion.
If both assertion and reason are hue but reason is not the correct explanation of assertion.
If assertion is true but reason is false.
If both assertion and reason are false.
structure of lenticel
hydathode showing gaseous vapour exchange
fungus reproducing by spore formation
algae reproducing by spore formation.
Identify the given figures A, B, C, D and E.
| A | B | C | D | E |
| Marginal | Axile | Free central | Parietal | Basal |
| A | B | C | D | E |
| Marginal | Parietal | Free central | Axile | Basal |
| A | B | C | D | E |
| Marginal | Axile | Parietal | Free central | Basal |
| A | B | C | D | E |
| Marginal | Axile | Parietal | Basal | Free central |
Which of the following is true?
Umbel is a racemose inflorescence where all stalked flower aggregate on the flat receptacle
Raceme is a racemose inflorescence having main axis shortened & flower born acropetally
Spadix is a racemose inflorescence having pendulous spike with main axis much flattened.
Spike is a racemose inflorescence having sessile flowers
Cocoa is the plant from which chocolate is made. Which part is used to extract it?
Flower
Fruits
Seeds
Bark
Ectophloic siphonostele is found in
Osmunda and Equisetum
Marsilea and Botrychium
Adiantum and Cucurbitaceae
Dicksonia and Maidenhair fern.
