Answer:
1. Green beetles and red beetles exist in the environment.
2. Birds that eat the beetles move into the environment.
3. Red beetles are eaten by birds, but green beetles aren’t eaten.
4. Green beetles pass on their color trait to future offspring.
5. The entire population of beetles eventually becomes green in color.
Explanation:
According to the theory of natural selection, only those species survives which fits closely with their environment. According to the conditions given, there are two genetic variations of the same species based on the color, i.e. green and red. Initially, both red and green are living together in a grassland (green in color). Then, birds enter the same environment because they have food there (beetles). Now, green beetles will take a competitive advantage because of the color and avoid getting eaten by the birds. However, red beetles would be prominent and eaten fast. The green beetles will pass on their genetic variation causing the color to be green in their future offspring and a time will come when there will be on green beetles in the area.
Pathogens generally invade the body, in their invasion they can duplicate and cause confusion such as hijacking your cells, thus they cause infection and disease. Some of these pathogens are spread through air, sweat, blood, excrete (urine/feces), or general human contact with anything concealing the pathogen.
Answer:
These crops can fix nitrogen into usable nitrates.
Explanation:
There are certain crops which are called cover crops, specifically legumes like peas, vetch,clover and winter field beans . Farmers grow these crops during winter before the growth of actual target crops like cabbage etc which are thirsty for Nitrogen.
What is special about these cover crops is their ability to fix nitrogen into the soil from the atmosphere. There are various ways through which these leguminous crops can fix nitrogen into the soil:
- Some legumes like hairy vetch and crimson clover, may fix upto 100 pounds of nitrogen per acre for the utilization by the crop growing in same soil next season.
- Other legumes like red clover and bigflower vetch can fix from 30 to 80 pounds of nitrogen per acre .
- Now how the legumes fix nitrogen is through a symbiotic relationship with soil-dwelling bacteria. These are the bacteria that dwell in soil and take nitrogen from atmosphere and provide this nitrogen to leguminous crops through roots which later fix this nitrogen into nitrates.In return, the bacteria can get food in the form of carbohydrates from legumes.
This phenomenon confers the leguminous crops with an ability to fix nitrogen in the soil that can be used by the nitrogen requiring crops like cabbage when grown next season in same soil.
Hope it help!
