Question

hi explain two types of movements in plants with one example of each

Answer 1

In plants two types of movements take place:

1. Tropic movements and
 2. Nastic movements

Phototropism
 The movement of a part of the plant towards light is called phototropism. Growth of aerial parts of a plant towards light is an example of phototropism.



2. Geotropism

The movement of a part of the plant towards gravity is called geotropism. Growth of roots of plants in downward direction is an example of geotropism.



3. Hydrotropism

The movement of a part of the plant towards water is called hydrotropism, e.g., movement of roots.



4. Chemotropism

The movement of a part of the plant towards a chemical is called chemotropism.During the process of fertilization the movement of pollen tube towards ovule due to secretion of a sugary chemical in the ovary is an example of chemotropism.



Nastic Movements

These are nondirectional movements which takes place neither towards nor away from the stimulus. The best example of nastic movement is folding and drooping of leaves of ‘touch me not’ plant when its leaves are touched with fingers

Answer 2

While it's common to think of the solar system's planets moving in circles, orbits are actually ellipses -- oval rather than perfectly round. If they were circles, the sun would be at the exact center of the orbit. That's not true for ellipses, though for most of the planets, it's pretty close. The orbit is the result of two competing forces, the straight-line motion of the planet through space pushing against the sun's gravity.