Answer:
A cell is made up of several molecules working together; a tissue is made up of many cells, working together; and an organ is made up of several tissues working together.
Explanation:
The correct answer is option (A) cattle egrets eating insects stirred up by grazing bison.
The cattle egret is a cosmopolitan species of heron and are white birds normally found sitting on the back of the cattle. They often accompany cattle or other mammals catching insects and small vertebrate prey which are disturbed by these animals. It is one of the popular examples of commensalism. It is a type of relationship in which one organism benefits from the relationship without harming the other organism. Cattle egret follow grazing cattle and eat flies which are dislodged by the movement of the livestock. They eat up the insects hiding in the vegetation closer to the grounds, which get stirred up when the cattle or grazing bison walk through them.
Answer:
Option A, oxygen in the atmosphere
Explanation:
The highest level of oxygen reached during this phase of the geological cycle of earth. The oxygen level in Carboniferous period accounted for 35% as compared to 21% of oxygen in the atmosphere in present time.
Due to high oxygen content, the giant and wide varieties of terrestrial animal and plant species evolved. For example – size of insects and carwlies increased, plant became extremely giant, increase in number of tree ferns etc.