Answer:
definition with benefit is given below of
1st. gravitropism
2nd. phototropism
3rd. thigmotropism
4th. photoperiod
Explanation:
1st is gravitropism
gravitropism is process in which plant grow in the direction that gravity act
It is also called geotropism
and
Gravitropism is important for plants because it directs the roots to grow in the downward direction that is important for obtaining nutrients
2nd is phototropism
phototropism is the process in which plant growth directed by the light
and
we know plants need light to carry out photosynthesis
so Phototropism direct the growth of the stem and branch toward sunlight
3rd is thigmotropism
thigmotropism is the directional change in growth of plant in response to a touch stimulus
and
thigmotropism is especially important for climbing plant that is use support to climb up
4th is photoperiod
photoperiod is the physiological change in organism in the response to length of the day and night
and
it play important role to determining the physiological developmental process in the plant such as budding and tuberization
Those small sections are called Genes
The Trachea
is your answer
hope this helps
