Questions

True. Hormones are chemicals secreted and regulated by the endocrine system.

Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the heritable traits characteristic of a population over generations.

When traveling in a vacuum, electronic waves from the electromagnetic spectrum all travel at the same speed. Velocity is speed with direction, so they would all travel at the same velocity, realtively speaking. But frequency and wavelength are quite different.

After the defeat of china by Japan in a war over Korea in 1894,France, Russia, Britain and Germany gave loan to china to help it to the payment of 150 million dollors demanded by japan. These western countries the divided china into spheres of influence, which meant that each country had certain regions of china reserved exclusively for its purposes.

          The united states feared that china would be completely parcelled out in exclusive 'spheres of influence' and that its trade with china would be shut off. The USA, therefore, suggested the policy known as the "Open Door". This policy is also described as "Mee too Policy".

          The division of China into "spheres of influence' has often been described as the "cutting of the Chinese melon".

The Law of Definite Proportion states that the same compound, wherever found or however made, always contains the same elements combined together in the same fixede ratio by weight.

The resistance of metallic conductors e.g, platinum, increases with rise of  temperature . The increase in temperature results in a decrease of current which can be recorded in a galvanometer if the conductor is included in an electrical circuit. Thus the temperature can be known; platinum resistance thermometer is used generally for accurate scientific work. When two dissimilar metals are joined at the ends, and these ends are subjected to a difference of temperature, a current flows through the metals. Greater the difference of temperature , greater the current. So the curent strength can form the basis for measuring the difference in temperature. And when one of these temperatures is known, we can calculate the other.