When we will cross them then the plants with purple and tallness traits=9, white tall plants=3,purple short plants=3,white short plant=1
So phenotype ratio is 9:3:3:1
Although the actual questions are missing from your ask, here's how you can tell.
If the study will be messed up (added bias) through interaction with the subjects the study should be observational. For example if a biologists wanted to study the eating habits of wild birds in the tropics, they would need to do an observational study. if they did a controlled experiment, the birds will change their eating habits based on human interaction, thus making the study invalid.
If the study requires specific measurements, close monitoring, or contact and interaction with the subjects the study should be a controlled experiment. For example, if a scientist wanted to test out a new drug, the health of patients would need to be closely monitored.
Pandas live for about 20 or so years
Answer:
relating to genes or heredity or relating to origin, or arising from a common origin.
Explanation:
