Answer:
During presentation of APC-bound antigen, macrophages and dendritic cells secrete the cytokine, interleukin-1, that activates T helper cells
Explanation:
Macrophages interact with T cells in order to generate T cell activation in target organs, and are themselves activated by inflammatory messenger molecules (cytokines) produced by the T cells.
Macrophages produce toxic chemicals, such as nitric oxide, that can kill surrounding cells.
During presentation of APC-bound antigen, macrophages and dendritic cells secrete the cytokine, interleukin-1, that activates T helper cells
Let us look at the what, why and how of studying extreme places like the deep earth and the deep space. Scientists need to figure out as to 'what' they want to look at such places, be it a new exotic creature or bio-genesis (birth of life). Unless there are several testable hypothesis constructed, such a study cannot begin. The 'why' aspect deals with the purpose of such research and expeditions. Is it of any use to the humans, or will it improve our current understanding of a phenomenon? The 'how' aspect deals with the technology and the economic assistance that can help in undertaking such a research. All these are the challenges that needed to be thoroughly considered to make such a research or expedition possible.
Answer:
(B) open stomata only at night, limiting water loss because of heat and low humidity.
Explanation:
CAM plants are found in the regions characterized by very hot and dry environmental conditions. These plants reduce the water loss through transpiration by exhibiting CAM photosynthesis.
They open the stomata during night time when the air is cooler and rich in moisture. They take in CO2 during night time and fix it into the oxaloacetate which in turn is converted into malate and is stored in the vacuoles.
During day time, stomata remain closed to prevent water loss and the CO2 trapped during night time (released by decarboxylation of malate) enter the Calvin cycle.
By definition, a body system is primarily comprised of different organs and tissues that work one another to achieve a common body process. These body systems would include:
Circulatory system - concerns with the circulation of blood
Digestive system - breaking down of food particles
Skeletal system - composed of bone structures serving as our body's framework
Nervous system - composed of nerve cells that responds to different stimuli
Respiratory system - concerns of utilising the entry of oxygen and the exhalation of carbon dioxide.
Answer:
Volume= 4 cm³
Density= 2 g/cm³
Explanation:
We have the following data:
volume= V= 8 cm³
mass= m= 16 g
The density is the mass per volume of a substance, so the density of the rock is:
density= d= 16 g/8 cm³= 2 g/cm³
When we cut the rock in half, we have a half volume and a half mass:
V= 8 cm³/2= 4 cm³
m= 16 g/2= 8 g
But the density is not altered because it is an intrisic property - it does not change with the amount of subtance. Thus, the density of a half rock is:
d = m/V= 8 g/4 cm³= 2 g/cm³
