Answer:
b. The water molecule is polar.
Explanation:
Water molecules forming hydrogen bonds with one another. The partial negative charge on the O of one molecule can form a hydrogen bond with the partial positive charge on the hydrogens of other molecules. Water molecules are also attracted to other polar molecules and to ions.
Answer:
Innate immunity is a non-specific immune system which provides defence against any pathogenic microorganism in early stages. It includes physical barrier such as skin, chemical barriers such as saliva, tears, et cetera, phagocytic cells such as macrophages, et cetera.
Acquired immune system is the one which develops after exposure to pathogen or antigen. It is highly specific in nature. It includes B-lymphocytes and T-lymphocytes. It includes the production of antibodies.
Vaccines are used to develop acquired immunity in people. The process is termed as vaccination or immunisation. Heat-killed or weakened pathogen or antigen is inserted into a person after which a person develops antibodies and memory cells against that pathogen or disease. So, the immune system acts more vigorously against that pathogen in secondary infection.
Thus, a person becomes immunised.
Answer:
D.The light-dependent reactions absorb sunlight and transfer the energy to electrons.
Explanation:
Firstly, the organelle that was described as small green organelle inside a cell as noticed by Quinlin is the CHLOROPLAST. Chloroplast is an organelle present in the cells of green plants, in fact, it makes plants green. Chloroplast is the organelle where the unique process of PHOTOSYNTHESIS occurs in plant cells.
However, the photosynthetic process is divided into stages namely: light-dependent and light-independent stages. The light dependent stage, which involves the production of ATP (energy carrier) and NADPH (electron carrier), must PRECEDE the light independent stage or Calvin cycle. Chloroplast contains a pigment called CHLOROPHYLL, which absorbs light energy from the SUN in order to power the light dependent stage of photosynthesis.
Hence, the light-dependent reactions, which absorb sunlight and transfer the energy to electrons must occur first in the organelle.
Carbon dioxide is added to the atmosphere naturally when organisms respire or decompose (decay), carbonate rocks are weathered, forest fires occur, and volcanoes erupt. Carbon dioxide is also added to the atmosphere through human activities, such as the burning of fossil fuels and forests and the production of cement.
