STD 12 - 12. ecosystem — NEET STD 11 Science — Question

Growth in plant organs is

Mark the given statements True (T) or False (F).
(i) Aristotle was the earliest scientist to attempt a more scientific basis for classification. He used complex morphological characters to classify plants into trees. shrubs and herbs.
(ii) Fungi have cellulose in their walls while green plants have chitin in cell wall.
(iii) According to five kingdom of classification, the unicellular prokaryotic organisms were placed in kingdom protista.
(iv) The classification system is not only based on morphological, physiological and reproductive similarities, but is also phylogenetic ie. is based on evolutionary relationships.
(v) Methanogens are present in the gut of several ruminant animals such as cows and buffaloes and they are responsible for the production of methane from the dung of these animals.
(vi) In Nostoc, site of oxygen fixation is heterocysts.
(vii) Cholera, tetanus, citrus canker are well known diseases caused by different bacteria.
(viii) Bacteria reproduce mainly by fission.
(ix) The mycoplasma are organisms that completely lack a cell wall. They are smallest living cells known and can survive without oxygen.
(x) Chrysophytes, Euglenoids and Slime moulds belong to kingdom protista.
Choose the correct option given below : -

Seed habit originated firstly in some

If all decomposers are removed from an ecosystem, what will happen

The phytohormone combination which is the key regulator of cell differentiation and morphogenesis is

Identify the incorrect match.

Following statements describe the characteristics of the enzyme Restriction endonuclease. Identify the Incorrect statement.

Choose correct statement for cytokine and mark correct option :
(i) It is a simple gaseous PGR.
(ii) It synthesised in large amounts by tissues undergoing senescence and ripening fruits.
(iii) Influences of it on plants include horizontal growth of seedlings, swelling of the axis and apical hook formation in dicot seedlings.
(iv) It promotes senescence and abscission of plant organs especially of leaves and flowers.
(v) It synthesised in regions where rapid cell division occurs, for example, root apices, developing shoot buds, young fruits, etc.
(vi) It helps to produce new leaves, chloroplasts in leaves, lateral shoot growth and adventitious shoot formation.
(vii) It help overcome the apical dominance.
(viii) They promote nutrient mobilisation which helps in the delay of leaf senescence.

Cytokinins are formed in