<span>Sclerenchyma cells are the strongest. They have a second cell wallwhich is hardened by lignin, making them very tough and durable.</span>
Answer:
Charles Darwin is best know for Natural selection
Answer:
The correct answer will be - Keystone species
Explanation:
Keystone species refers to the species present in a community which has a large effect or great influence on the surrounding environment.
The concept of Keystone species was introduced by the Robert T. Paine in 1969 to the species which help maintain the structure of the biological community.
The keystone species are called keystone species as its presence affect the other organisms directly and if removed from a community it will lead to the shift or change in the structure of the community.
Thus, Keystone species is the correct answer.
Our sleep cycle is a circadian rythm but without the options I can't give a definite answer
1. Rhythm generators (SA node)
2. Conductive cells (node cells)
3. Contractile cells (myocardial cells)
