Answer:
Experimental set up in the lab.are under the control of the scientist,therefore they can manoeuvre the the surrounding conditions to suit the experimental set up for best results. In addition the lab.environment does not involve the complex interactions or reaction between the set up and the lab. environments, compare to the natural environment.
Natural experimental set up gives accurate results from the interaction of the organisms(e.g animals) under investigation in the natural environments,thus the results obtained are natural interaction of the organisms based on the environmental factors the organism are exposed to.However, the number of organisms are usually large,and therefore great effort is needed to determine the actual cause and effects of the factors affecting the organisms under investigations in this natural environments.
<span>Vacuoles are organelles present in plant cells, some animal, and some prokaryotic cells. There is a difference in size between plant and animal cells. Plant cells usually have one large vacuole while animal cells have a number of small vacuoles. If the term "small vacuoles" is used for vacuoles in animal cells, then they are involved in overcoming the foreign particles, storage of waste and during the exocytosis, and invagination of the cell membrane during engulfing the bacteria.</span>
Ans.
Steroids are defined as active organic bio-molecules, having four rings with a specific molecular configuration. Steroids play role in two major functions: as hormones or signaling molecules and as structural components of plasma membrane.
Examples of steroid hormones are estrogen, progesterone, and cortisol. Thus, the correct answer is 'option b). they serve as chemical messengers.'
(4) Personal habits, such as hand washing, have
<span>greatly reduced contamination from bacteria.</span>
The leaves of forest trees have adapted to cope with exceptionally high rainfall. Many tropical rainforest leaves have a drip tip. It is thought that these drip tips enable rain drops to run off quickly. Plants need to shed water to avoid growth of fungus and bacteria in the warm, wet tropical rainforest
