Approximately how many tweets are posted on Twitter each day? 500 500 thousand 500 million 500 billion

Selling a product through an electronic medium is

To produce a starlight effect in her photograph, lina should choose the filter for her camera.

4. what is the reason for including the following code snippet in the header file animal. h? #ifndef animal_h #define animal_h class animal { public: animal(); animal(double new_area_hunt); void birth(); void hunt(double new_area_hunt); void death(); double get_area_hunt() const; private: double area_hunt; }; #endif