I think D is the right answer.
<span>According to the nebular theory stars are formed in which sequence:
a. Interstellar clouds - "nebula" is a Latin word which means clouds. These clouds start to form and are composed of gases like hydrogen and helium.
b.Clumps - as the gases start to form and come together they form clumps of gases that are highly concentrated and they start to grow.
c. Gravitational forces - when clumps have grown into big sizes the gravitational forces that are found within it increases and are converted into kinetic energy of fast-moving particles that continuously bump into each other and create or generate heat.
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d. Nuclear fission - as the clumps keep on colliding and creating heat (18 million degrees Fahrenheit), nuclear fission begins.
e. Outward pressure from the nuclear fission prevents the collapse of the gases, stabilizing the gases eventually creating a star. </span>
Ecologists are the persons who study the interrelationships between organisms and their environments. Like they research upon the species found in forests or deserts interact with each other and as well as their surroundings.
They test whether a species is occupying its complete fundamental niche or only a portion of it by observing if the species are expanding their range after the removal of a competitor because two species with the same fundamental niche will exclude other competing species.
16 percent of the world's population and 50 percent of the Christians population.