Rabbits and Hares

Rabbits and hares belong to the same category of animals – mammals. Hares have longer ears and are generally larger and faster than rabbits. Hares have larger feet and more extended, more muscular hind legs than rabbits. Hares’ fur has distinguishing black markings. A rabbit, on the hand, can be your best pet, but a hare cannot. Rabbits are smaller and fluffier. Even their diets differ from each other. Rabbits prefer vegetables like carrots and soft grass, whereas hares prefer small branches and wood bark. Hares are solitary animals, whereas rabbits are social. Unsurprisingly, rabbits are easy to domesticate, while hares are primarily feral. Hares are precocial, meaning they are born with their eyes open, and their fur grows throughout, so they don’t require much parental care. While rabbits are born naked, blind, weak, and vulnerable, they prefer to live in underground dens. Long ears, strong back legs, and a divided upper lip are present in both animals.

Frogs and Toads

Amphibians are animals that can live on land and in water. Frogs and toads are examples of amphibians that can be found on all continents except Antarctica. Sometimes, toads are confused with frogs because of their certain similarities. Both have a similar appearance: a wide head, short, rigid body, two front arms, and two hind legs. Both are carnivores that catch their prey with their long, sticky, and protruding tongues. Frogs have moist and smooth skin, teeth in their upper jaw, longer legs for hopping, and bulging eyes that can protrude farther than a toad’s.

In contrast to frogs, the skin of toads is dry and rough and covered with warts all over its body. Toads lack teeth and have relatively shorter hind legs suitable for crawling. Another distinction is that toads lay their eggs in a string, whereas frogs cluster their eggs in a grape-like structure. Toads are land animals that can be found in fields, forests, and gardens. They are also nocturnal, meaning that they sleep all day while remaining active at night. Frogs need to keep their skin wet, so they tend to live near any water area. Frogs are active during the day and at night. Although both animals are solitary, the toads tend to live in groups when hibernating and mating.

Earth and Mars

Mars is about half the size of Earth and has a significantly thinner atmosphere, with less than 1% of Earth’s atmospheric capacity.   The atmosphere of Mars is predominantly carbon dioxide-based, whereas the atmosphere of Earth is nitrogen- and oxygen-rich. Earth and Mars have seasons, moons, snow, ice, and volcanoes. Liquid water covers over 70 percent of the Earth’s surface. Mars doesn’t have liquid water on its surface; it is covered with barren rock and dust. The sun raises the temperature of the Earth’s surface to above 100 degrees Fahrenheit. The temperature on Mars rarely rises above freezing. The gravitational force on the surface of Mars is just 38% as powerful as it is on Earth’s surface. Since Mars rotates slower than Earth, each day on Mars is a little longer. It lasts for a total of 24 hours and 37 minutes. Sol is the name for a day on Mars. The orbit of Mars is greater than that of Earth. Mars travels through space at a slower rate than Earth. A year on Mars lasts 669 sols due to the size and speed of its orbit. The orbit of the Earth is almost round, whereas the orbit of Mars is more elliptical.

Stars and Galaxies

A galaxy is a massive cluster of stars bound together by gravitational attraction. A solar system is a collection of celestial bodies that orbit around the sun due to its powerful gravitational pull. Solar systems orbit their galaxies the same way planets orbit their suns. The orbit of the Earth’s solar system takes about 200 to 250 million years to complete. Galaxy contains a black hole at its center, and it can have any shape or size based on which they are classified into different categories. A galaxy can have a million to a trillion stars in it. Dark matter can exist in a galaxy but not in a solar system. The planet Earth and the solar system are part of the Milky Way galaxy. The galaxy might contain 200 billion stars. The solar system has the sun at the center, and there is no defined shape, so unlike galaxies, there is no classification based on their shape. There is only one star in a solar system, around which the planets orbit.

Pluto and Mercury

In 1930, Pluto was the smallest planet in our solar system. Before 1930, Mercury was considered the smallest planet. Later in 2006, astronomers excluded Pluto as a planet, and Pluto is now considered a “dwarf planet.” Mercury is about two times larger than Pluto. Mercury consists of rock and metal, whereas Pluto consists of ice and rock. Mercury has a density of 5.427 g/cm3, while Pluto has a density of roughly 2 g/cm3. Pluto has a far lower gravitational force than Mercury because it is smaller and less dense. Mercury is the closest planet to the Sun, orbiting at a distance of only 57.9 million kilometers, whereas Pluto is at a distance of 5.9 billion kilometers. Mercury completes one orbit in 88 days, while Pluto takes 248 years to complete one orbit around the Sun. Pluto contains at least three moons and may have faint ice rings, whereas Mercury has neither rings nor moons. Mercury can be seen without a telescope. Pluto, on the other hand, needs an extremely powerful telescope.

Mules and Donkeys

Mules and donkeys are frequently confused because mules have a donkey-like appearance. A mule is a crossbreed of a jack, a male donkey, and a mare, a female horse. Generally, mules cannot mate; however, there have been cases where fertility was possible. In contrast to donkeys, mules have more prominent ears as they get them from their mothers. In size, mules are the only half size of donkeys. Similar to a horse, they have a larger and taller body. Their teeth, tails, and coats resemble those of donkeys, however. Mules inherit strength and stamina from horses, and just like donkeys, mules are patient and intelligent with even temper. Mules are infertile, but mollies, female mules, have been known to produce milk. Broad-leaved plants and roughage like barley straw are favorites of both donkeys and mules. However, as a precaution, donkeys are not fed large amounts of bread, protein, puffed rice, or any processed food because they may develop foot diseases. There are about 12 million mules present, about 3 million present in China and Mexico alone. There are about 19 million donkeys across the globe, with more than 3 million in China, 2 million in Pakistan, and 1.5 million in Ethiopia, Mexico, and Egypt.

Planets and Stars

In the night sky, you may see stars and planets that come in various sizes. Planets and stars are comprised of gas and dust; both have a very hot core. A star is a dot-shaped body with a light source that enables it to reflect light on its own, and a planet is a spherical-shaped, fixed celestial entity that orbits and spins on its axis that is reflecting light from an external source. Planets do not have an inherent light source; thus, they rely on other sources for illumination, primarily the Sun. Even though planets appear to be huge in photographs and stars appear to be far away and little, stars are gigantic in comparison to planets. The primary composition of stars consists of hydrogen, helium, and some other elements; they can have very high temperatures. Stars shift their position, but this can only be noticed after a considerable time due to the great distance. In contrast to planets, stars travel at a faster rate. Compared to stars, the temperature of the planet is low. Planets revolve on their axis and continually shift their positions. They consist of solids, liquids, gases, or a combination of all three.

Turtles and Tortoises

Turtles and tortoises are reptiles. Both have four legs and are mobile but slow. Both have scales and a hard shell; they bury their eggs in sand, soil, or vegetation. Turtles and tortoises are ectothermic, which means they maintain their body temperature using external sources such as exposure to sunlight. They don’t have teeth, so they bite with the hard edges of their mouths. Tortoises are mostly found in Asia and Africa, and turtles are majorly present in Africa and America. The main distinction between the two is in the places where they live. Turtles spend most of their lives in the water and have webbed feet for swimming. Their shells are flatter, lighter, and streamlined. It has markings resembling the stains and circles on the water to help them blend in ponds. This enables turtles to hide in their habitat. Tortoises are land animals with stumpy, non-webbed feet that assist them in digging and navigating rough land. Shells of tortoise are thicker and dome-shaped. Fish, Plants, worms, and insects are all eaten by most turtles as they are omnivores. While most tortoises are herbivores who eat shrubs, grasses, and flowers, some species eat insects and worms too.


In a scientific experiment, an independent variable is a variable that is modified or manipulated to see how it affects the dependent variable. A dependent variable is a variable that is being tested and measured. The independent variable affects the dependent variable. The effect on the dependent variable is recorded when the investigator alters the independent variable. The independent variable is the one that the researcher alters or manipulates. As a result, it’s often referred to as a manipulated variable or an explanatory variable. In a graph, dependent variables are plotted on the y-axis, while independent variables are plotted on the x-axis. While both variables are part of a scientific experiment, they play different roles and functions when it comes to their application.