Dona wrote the characteristics of two types of galaxies as shown below: Type A: Has a large flattened core Type B: Does not have
a regular shape Which statement is correct? Type A is an irregular galaxy and Type B is a lens galaxy. Type A is a lens galaxy and Type B is an irregular galaxy. Type A is a spiral galaxy and Type B is an elliptical galaxy. Type A is an elliptical galaxy and Type B is a spiral galaxy.
Since the industrial revolution, human activities have also resulted in an increase in natural greenhouse gases, especially carbon dioxide. An increase in these gases in the atmosphere enhances the atmosphere's ability to trap heat, which leads to an increase in the average surface temperature of the Earth.
Decline in the global population of amphibians is due to multiple reasons which include:
A moist ecosystem is necessary for amphibians especially for the purpose of their reproduction. The drainage of the wetlands deprives them of their habitat.
Pollutants adversely affects the survival of the gametes, tadpoles or the adult amphibians by acting as toxic agents and inhibiting their normal metabolic function.
Infectious diseases often cause their death resulting their population to decline.
Global climate warming affects their normal metabolic growth and development and hence causes their population to decline.
The cholodny-went model was proposed in 1927. This model explains the capability of the shoots to grow in the direction of the sunlight whereas the capability of the roots to grow downwards. The hypothesis suggested that both these directional growth occurred due to the asymmetrical distribution of the plant hormone, auxin. This model has been modified a number of times by other scientists but its general concept is accepted by most of the researchers.
