1) Interphase is the longest phase and most of the cells are present in that very stage !!
2) Interphase is the longest phase and Anaphase is the shortest phase !! Interphase is the longest phase as in this phase the cells prepare themselves for dividing and it takes most of the time for gathering energy for division ; in this phase DNA also replicate !!
3)
Interphase: DNA replicates;
Prophase: Nuclear membrane starts disappearing and Centrioles go on opposite poles !! DNA condense to form Chromosome.
Metaphase: Chromosome attach to spindle fibre and starts to move to equitorial plate.
Anaphase: Centromere divide and half the chromatid goes on either pole
Telophase: Nuclear membrane starts to reassemble; Chrmosome goes to normal uncoiled state ; Other organelles starts appearing
Cytokinesis: Cell furrow forms and cell divides into two half.
4) In dividing cell nucleus membrane is absent while in non dividing cell the membrane is intact
5) Tip of the onion root is meristamatic cell which divides but if it is permanent cell ; there would be no division !!
Answer: To attract a Mate
Explanation: In competition, males use feather color to warn potential rivals that they occupy a piece of territory. When it's time to mate, male birds show off their plumage to attract a mate. In experiments, female birds prefer males with more fanciful feathers, or brighter colors.
<span>the correct answer is B. the information that decides the characteristics of all organisms are contained in their nucleic acids. Nucleics acids are DNA and RNA. DNA have genes that code for proteins which are responsible for the structural and functional characteristics of organisms. DNA is transcribed into RNA and RNA is translated to proteins. Therefore information that is in these nucleic acids determines all the characteristics of organisms</span>
Answer:
The receptor senses changes in the environment and responds by sending information (input) to the control center along the ascending pathway. The control center analyzes the input, determines the appropriate response, and activates the effector by sending information along the descending pathway. When the response causes the initial stimulus to decline, the homeostatic mechanism is referred to as a negative feedback mechanism. When the response enhances the initial stimulus, the mechanism is called a positive feedback mechanism. Negative feedback, mechanisms are much more common in the body.
Explanation:
Homeostasis is the adaptation of living organisms or systems to new conditions in the environment by auto-regulation. Through this mechanism, an equilibrium state can be maintained in spite of any changes. This adjustment in the physiological system is called <em>homeostatic regulation</em> and it is composed of three parts: the receptor, the control center, and the effector.
The receptors receive information from the environment about something changing and transmit that information to the central nervous system (control center). This pathway is defined as the ascending pathway. Information is processed in the control center which handles many sensory signals, evaluates them, compares them and uses them for decision making. After that, an efferent neuron is stimulated to carry information from the central nervous system to the effector cells of the target organ. The effector may be muscle or glandular tissue. This pathway is defined as the descending pathway. Finally, the target organ responds.
There is negative feedback when the response declines the initial stimulus, which is the <u>most common mechanism</u> in the body. There is positive feedback when the response enhances the initial stimulus, which might be very nocive to the organism.
