Diatoms are the chief producers in some oceans and in some seasons as they are the primary producers and the food chain in marine ecosystem depends on it.
123.
One scientist cultured Cladophora in a suspension of Azotobacter and illuminated the culture by splitting light through a prism. He observed that bacteria accumulated mainly in the region of :
Azotobacter is aerobic bacteria. and Cladophora is green alga.
Engelmann used a prism to split light into its spectral components, and then illuminated a green alga, Cladophora, placed in a suspension of aerobic bacteria. The bacteria were used to detect the sites of oxygen evolution.
He observed that aerobic bacteria accumulated mainly in the region of blue and red light of the split spectrum thus giving the first action spectrum of photosynthesis. Note : Theodor Wilhelm Engelmann was a German botanist, whose 1882 experiment measured the effects of different colours of light on photosynthetic activity and showed that the conversion of light energy to chemical energy took place in the chloroplast.
124.
Viruses are no more "alive" than isolated chromosomes because
A
both require the environment of a cell to replicate
B
they require both RNA and DNA
C
they both need food molecules
D
they both require oxygen for respiration
Answer :
both require the environment of a cell to replicate
Chlamydomonas & Chlorella have been included in algae. Algae are chlorophylus, thalloid avascular plants with no cellular differentiation. Algae belong to thallophyta of plant kingdom.
126.
Absorptive heterotrophic nutrition is exhibited by