There are two types of polymers which are natural and synthetic polymers. Natural polymers do not affect the environment but synthetic polymers do. This type of polymers are produced by humans. These release reactants which are considered hazardous to humans and the environment. Synthetic polymers include rubbers, plastics, and adhesives, and these are considered non-biodegradable and non environmental friendly. As these build up in the environment, in causes problems such as chemical poisoning to all the living things around it.
Answer:
Option A, Hormones are controlled by a feedback loop; information about a system is sent back to the controller of the system to improve its function.
Explanation:
Negative feedback loop controls the hormone production and release. This is done by eliciting the release of substances till a certain level after which the stop signal is activated thereby preventing further release. By this method, concentration of hormones in blood is maintained within the narrow range.
For example – Thyroid hormones is released when the anterior pituitary signals the thyroid. This continues till the hormones in the blood reach the threshold level. Once the threshold level is reached, hypothalamus receives a feedback and then signals anterior pituitary to inhibit further signaling to the thyroid
Hence, option A is correct
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 !!
Since the gravitational force is directly proportional to the mass of both interacting objects, more massive objects will attract each other with a greater gravitational force. So as the mass of either object increases, the force of gravitational attraction between them also increases. If the mass of one of the objects is doubled, then the force of gravity between them is doubled. If the mass of one of the objects is tripled, then the force of gravity between them is tripled. If the mass of both of the objects is doubled, then the force of gravity between them is quadrupled; and so on.
Hope this helps.
The right answer is: Leptin
.
Leptin is a hormone closely linked to the regulation of energy consumption and expenditure: appetite, metabolism, and hunger.
A hormone is a protein with a messenger function. This means that once released into the bloodstream, she goes to another part of the body to transmit a message to specific receptors.
Leptin is manufactured in white adipocytes (adipose tissue) where triglycerides (fats) are stored and acts on the hypothalamus.
