Answer:
Because they do not live in the extreme environments.
Explanation:
Cell membrane has a vital role in separating the external environment of cell from its external environment. Just like eukaryotic cell, cell membrane of bacteria is also composed of proteins and lipids (phospholipids).
If we compare the structure of ancient bacteria's and modern bacteria's cell membrane then we notice that in archaebacteria or ancient bacteria the phospholipids of cell membrane are linked with ether (means they have glycerol backbones). whereas in modern bacteria they are linked through ester linkages.
So, the stronger glycerol backbones give the archaebacteria more stable cell membranes through which they are able to resist harsh environmental stresses like salt lakes, volcanic stress, boiling mud and hot springs. As modern bacteria do not always have to live under such stresses thats why they donot have ether-linked cell membrane.
Hope it helps!
Science definitions for producer. An autotrophic organism that serves as a source of food for other organisms in a food chain. Producers include green plants, which produce food through photosynthesis, and certain bacteria that are capable of converting inorganic substances into food through chemosynthesis.
Answer:
3, 5, 1, 4, 2.
Explanation:
Neurons are the structural and the functional unit of the nervous system. Two main types of neurons on the basis of their function are sensory neurons and motor neurons.
The motor control in order body occurs in a sequential step. The motor program is selected by the pre motor cortex. This neuron is further stimulated by basal nuclei of the thalamus. This further stimulate the lower motor neuron. This causes the contraction in the skeletal muscle. This information is further move to cerebellum if movement is required.
Thus, the correct order is 3, 5, 1, 4, 2.