Ethylene stimulates leaf release, while auxin keeps leaves from falling.

Plant growth is stimulated by the presence of auxins, ethylene and abscisic acid.

Assertion: on stimulation, a muscle cell releases calcium ions (Ca^(2+)) from sarcoplasmic reticulum. Reason: By reacting with a protien complex, Ca^(2+) uncover active sites on the actin filaments.

Pick up correct statements (A) Cytokinins delay senescence (B) Auxin regulate apical dominance (C) Ethylene enhances seed germination (D) Gibberellins cause falling of immature leaves.

[A]: In vertebrates, motor fibres to striped muscle, parasympathetic fibres to smooth muscle, and preganglionic sympathetic fibres are cholinergic. [R]: Cholinergic designates the type of nerve fibre that releases acetylcholine from its ending when stimulated by a nerve impulse

Extrusion of electron from reaction centre of PS II leaves a hole which is filled by electron released from

[A] : Upon stimulation of a muscle cell, cal- cium ions (Ca^(++)) are released from the sar- coplasmic reticulum. [R]: In reacting with a protein complex, Ca^(++) unmasks myosin binding sites on the ac-tin filaments.

The hormone that promotes milk release from breasts and that stimulates uterus to contract is