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
The answer is C. Maybe im not sure
Answer:
A. the sun rotates at the same rate throughout
Explanation:
Answer:
PFFT this might help? sorry if not mate
Explanation:
Cell cycle checkpoint controls play a major role in preventing the development of cancer [see Sherr, 1994, for a more detailed discussion]. Major checkpoints occur at the G1 to S phase transition and at the G2 to M phase transitions. Cancer is a genetic disease that arises from defects in growth-promoting oncogenes and growth-suppressing tumor suppressor genes. The p53 tumor suppressor protein plays a role in both the G1/S phase and G2/M phase checkpoints. The mechanism for this activity at the G1/S phase checkpoint is well understood, but its mechanism of action at the G2/M phase checkpoint remains to be elucidated. The p53 protein is thought to prevent chromosomal replication specifically during the cell cycle if DNA damage is present. In addition, p53 can induce a type of programmed cell death, or apoptosis, under certain circumstances. The general goal of p53 appears to be the prevention of cell propagation if mutations are present. The p53 protein acts as a transcription factor by binding to certain specific genes and regulating their expression. One of these, WAF1 or Cip1, is activated by p53 and is an essential downstream mediator of p53-dependent G1/S phase checkpoint control. The function of p53 can be suppressed by another gene, MDM2, which is overexpressed in certain tumorigenic mouse cells and binds to p53 protein, thus inhibiting its transcriptional activation function. Other cellular proteins have been found to bind to p53, but the significance of the associations is not completely understood in all cases. The large number of human cancers in which the p53 gene is altered makes this gene a good candidate for cancer screening approaches.
