False
Environmentalists are complaining now about so-called "issues" more than ever.
Answer:
Any object that is spherical in shape would best represent a true scale model of the shape of the Earth.
for example: ping pong balls, billiard balls, marble and other smooth spherical objects. The shape of the Earth is called the oblate spheroid.
Answer:
is this it?
Explanation:
Cytotoxic CD8 T cells carry out their killing function by releasing two types of preformed cytotoxic protein: the granzymes, which seem able to induce apoptosis in any type of target cell, and the pore-forming protein perforin, which punches holes in the target-cell membrane through which the granzymes can enter.
Answer:
when the North Pole tilts toward the Sun, it's summer in the Northern Hemisphere. And when the South Pole tilts toward the Sun, it's winter in the Northern Hemispher
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!
