The answer that makes most sense to me is D. We stopped needing to kill whales, yay! :P
Parasitism is when one organism benefits at the cost of it's host. Like fleas on a dog or intestinal parasites to livestock. Fleas and intestinal worms get food and a nice place to livr, while the dogs and the livestock are being leeched off of and malnourished.
Commensalism is when one organism benefits, while the host is left unharmed- but also doesn't really get anything in return, unlike mutualism. Like a shark and remoras (those fish with suction-cup heads & hitchhike). Sharks aren't hurt, but the remoras get free transportation and access to food scraps.
Hope this helps!
Answer:
Explanation:
Because they appeared quickly in geological time, and moulted like other arthropods, trilobites serve as excellent index fossils, enabling geologists to date the age of the rocks in which they are found. They were among the first fossils to attract widespread attention, and new species are being discovered every year.
Answer:
The environmental impact of a food is the effect that the entire production chain has. From the primary, continuing with the stages of transformation, distribution, use and final disposal. This can translate into: * Global warming
The two main variables in an experiment are the independent and dependent variable.
An independent variable is the variable that is changed or controlled in a scientific experiment to test the effects on the dependent variable.
A dependent variable is the variable being tested and measured in a scientific experiment.
The dependent variable is 'dependent' on the independent variable. As the experimenter changes the independent variable, the effect on the dependent variable is observed and recorded.
For example, a scientist wants to see if the brightness of light has any effect on a moth being attracted to the light. The brightness of the light is controlled by the scientist. This would be the independent variable. How the moth reacts to the different light levels (distance to light source) would be the dependent variable.
When results are plotted in graphs, the convention is to use the independent variable as the x-axis and the dependent variable as the y-axis.
