Helper T cells <span>are required for almost all </span>adaptive immune responses<span>. They not only help activate B </span>cells to<span> secrete antibodies and macrophages </span>to<span> destroy ingested microbes, but they also help activate cytotoxic </span>T cells to<span> kill infected target </span>cells<span>.</span>
Efferent nerve any nerve that carries impulses from the central nervous system toward the periphery, such as a motor nerve
Answer:
The correct answer is d. Oxygen
Explanation:
Phytoplanktons are responsible for the fixation of approximately half of the global carbon therefore seawater has high CO2 concentration which is required by phytoplanktons to make their food.
They are the primary producers of oceans and they are responsible to support the food chain of oceans. Factors that can limit their growth are mainly sunlight and nutrients like phosphorus, nitrogen, etc.
As phytoplanktons are photosynthetic they release oxygen itself as a byproduct therefore oxygen is not a limiting factor to phytoplanktons. So the right answer is d.
Answer:
Option A
Explanation:
Only an autotrophic species can convert methane into food.
Deep below the sea, methane and hydrogen sulfide are found in abundance. These gases get mixed into the sea water.
Autotrophic bacteria containing phosynthetic pigments oxidize these dissolved gases thereby producing food.
Hence these autotrophic bacteria’s will be considered as producers as they produce food.
Thus, option A is correct.
