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.
Answer:
<h2>False</h2>
Explanation:
Natural killer cells (NK cells) are a type of lymphocyte and also a component of innate immune system. NK cells play various functions in immune system and they play a major role in the host-rejection in virally infected cells.
NK cells are activated in response to interferons and also by various other responses. NK cells work to by secreting IFNγ and TNFα. Natural killer cells play a very important role in early host defense against viruses.
Answer:
the answer is biochemistry
Answer:
Algal blooms occur when algae multiply very quickly. Blooms can form in waters that are rich in the nutrients the algae need to grow, such as nitrogen, phosphorous, and iron. ... Blooms may become more frequent as the earth warms and the levels of nutrients in our waters increase.
The flower is called a producer because it produces its own food. The frog is a consumer because it needs to eat other plants to get its food and does not make its own.
