Answer:
Photoperiodism is a plant's response to the number of hours of darkness in its environment. b. Plants that flower when exposed to less than 10–12 hours of darkness are called long-day plants.
Explanation:
Answer:
Dmitri Ivanovsky
Explanation:
Dmitri Ivanovsky utilized one of these filters in 1892 to demonstrate that despite being filtered, sap from a diseased tobacco plant remained infectious to healthy tobacco plants. The filtered, infectious substance was dubbed a "virus" by Martinus Beijerinck, and this discovery is regarded as the origin of virology.
100,000 years ago is your answer
There is no element with one valence electron and six energy levels. Only two valence electrons and six energy levels.
Answer:
Calcium
Explanation:
A: Calcium is a group 2 element with two valence electrons. Therefore, it is very reactive and gives up electrons in chemical reactions. It is likely to react with an element with six valence electrons that “wants” to gain two electrons. This would be an element in group 6, such as oxygen.
