Showing
7
question(s) for
UK Class 9
—
Subject:
Science
Science
Q1.
Why does diffusion occur?
Answer:
Diffusion occurs because particles move randomly from a region of higher concentration to a region of lower concentration until they become more evenly distributed.
Science
Q2.
What is the difference between aerobic and anaerobic respiration?
Answer:
Aerobic respiration releases energy using oxygen, while anaerobic respiration releases energy without oxygen and produces different waste products.
Science
Q3.
Why does the mass remain conserved during a chemical reaction?
Answer:
Atoms are rearranged during a chemical reaction but are not created or destroyed, so the total mass of the reactants equals the total mass of the products in a closed system.
Science
Q4.
What is the relationship between voltage, current and resistance?
Answer:
Ohm's law states that voltage equals current multiplied by resistance, expressed as V = IR, under conditions where the resistance remains constant.
Science
Q5.
Why does increasing resistance reduce current when voltage is constant?
Answer:
According to Ohm's law, I = V/R. If voltage remains constant and resistance increases, the current must decrease.
Science
Q6.
What is natural selection?
Answer:
Natural selection is the process by which individuals with advantageous inherited characteristics are more likely to survive and reproduce, causing those characteristics to become more common over generations.
Science
Q7.
Why can a small change in an ecosystem affect many organisms?
Answer:
Organisms in an ecosystem are interconnected through food webs and environmental relationships, so a change affecting one population can alter resources, predators, competitors and other populations.