The correct answer is 1 and 4.
Burning of fossil fuels releases harmful gases to the atmosphere which leads to climate change. Burning of hydrogen gas releases water which has no negative effect on climate.
Burning of both fossil fuels and hydrogen takes place inside expensive fuel cells.
Fossil fuels are widely available and easy to locate whereas hydrogen is available in the combined form with other elements. Hydrogen are not found in pure form on earth.
Fossil fuels are non-renewable source of energy which means they cannot be replaced in short time.
Newton's first law of motion says something like "An object remains
in constant, uniform motion until acted on by an external force".
Constant uniform motion means no change in speed or direction.
If an object changes from rest to motion, that's definitely a change
of speed. So it doesn't remain in the state of constant uniform
motion (none) that it had when it was at rest, and that tells us
that an external force must have acted on it.
And because of gravity it falls back down to the earth.
<u>Answer</u>
1) A. 96 Candelas
2) A. Both of these types of lenses have the ability to produce upright images.
3) C. 5 meters
<u>Explanation</u>
Q1
The formula for calculation the luminous intensity is;
Luminous intensity = illuminance × square radius
Lv = Ev × r²
= 6 × 4²
= 6 × 16
= 96 Candelabra
Q2
For converging lenses, an upright image is formed when the object is between the lens and the principal focus while a diverging lens always forms and upright image.
A. Both of these types of lenses have the ability to produce upright images.
Q3
Luminous intensity = illuminance × square radius
square radius = Luminous intensity/ illuminance
r² = 100/4
= 25
r = √25
= 5 m
<span>1.
</span>Meiosis has 2 cell divisions but mitosis has only one cell
division. Meiosis I is same as mitosis because parent cell produces diploid
cells. But the difference between meiosis and mitosis is after the complete
process meiosis produces genetically different haploid daughter cells and
mitosis produces genetically same diploid daughter cells.
<span>2.
</span>The main advantage of the sexual reproduction is It helps to produce offspring which can be
well adapted to the environmental conditions due to the genetically
differentiations. Hence, there are various types of offspring in the population.
But the disadvantage is it requires two parents and it requires more time than
asexual reproduction.
<span>3.
</span>Advantages
of asexual reproduction are it requires only parent, time for the process is
relatively low, it produces genetically identical offspring. The main
disadvantage is due to the production of genetically identical offspring, the
survival rate is low when there is a disaster.
<span>4.
</span><span>The
organism can do either sexual reproduction or asexual reproduction to produce
offspring. If it is difficult to find a partner to mate, the living being can
do asexual reproduction to make offspring in a short period of time. When the
organism needs genetically different offspring for survival, they can do sexual
reproduction.</span>
