Science 7 Recall

It is an instrument used to obtain a magnified image of minute objects or minute detail of objects.

• microscope

• test tube

• computer

• lens

Answer explanation

The correct answer is 'microscope' because it is specifically designed to magnify small objects or details, unlike the other options which serve different purposes.

What makes prokaryotes different from eukaryotes?

• They do not have true nucleus and membrane-bound organelles

• They are larger and have more chromosomes

• They are present in higher forms of organisms

• They have a distinct nucleus and organelles

Answer explanation

Prokaryotes are distinct from eukaryotes because they lack a true nucleus and membrane-bound organelles, which are characteristic features of eukaryotic cells. This fundamental difference defines their cellular structure.

What is the total magnification of the image of an object under a microscope if the ocular has a magnification of 5x while the objective lens is 10x?

• 50x

• 40x

• 15x

• 5x

Answer explanation

To find the total magnification, multiply the ocular magnification (5x) by the objective lens magnification (10x). Thus, 5x * 10x = 50x, making the correct answer 50x.

These organelles are found only in plant cells and make plants unique to other living things.

• vacuole & lysosomes

• capsule & flagellum

• ribosomes & cell membrane

• plastids & chloroplasts

Answer explanation

Plastids, including chloroplasts, are unique to plant cells and are essential for photosynthesis, making plants distinct from other organisms. Vacuoles are present in both plant and animal cells, while lysosomes are primarily in animal cells.

It is a step-by-step procedure by which information is obtained in a precise and orderly manner, and from which conclusions can be drawn.

• inquiry

• forecast

• observation

• scientific method

Answer explanation

The scientific method is a systematic process for gathering information and drawing conclusions. It involves steps like observation, hypothesis formulation, experimentation, and analysis, making it the correct choice for the given definition.

It is the possible solution to the problem; also known as “educated guess”.

• conclusion

• hypothesis

• experiment

• inference

Answer explanation

A hypothesis is an educated guess that proposes a possible solution to a problem. It is a starting point for further investigation, distinguishing it from a conclusion, experiment, or inference.

It is a classification of matter which exists in one phase and cannot be separated by physical means.

• pure substance

• alloy

• mixture

• solution

Answer explanation

A pure substance is a form of matter that has a constant composition and cannot be separated into components by physical means, distinguishing it from mixtures and solutions.

Which is true about solutes?

• It is the dissolving medium

• It is present in lesser amount

• it is dissolved in a substance

• 2nd & 3rd choices

Answer explanation

Solutes are substances that are dissolved in a solvent. They are present in lesser amounts compared to the solvent, making the 2nd and 3rd choices correct. The first choice describes the solvent, not the solute.

This idea or statement forms and supports the cell theory.

• All living things are made of cells

• All plants and animals are made of cells

• All cells arise from preexisting cells

• ALL OF THE ABOVE

Answer explanation

The cell theory states that all living things are composed of cells, all plants and animals are made of cells, and all cells originate from preexisting cells. Therefore, the correct answer is 'ALL OF THE ABOVE'.

The following are colloids, EXCEPT:

• peanut butter

• toothpaste

• mouthwash

• ketchup

Answer explanation

Mouthwash is a solution, not a colloid, as it does not contain dispersed particles. In contrast, peanut butter, toothpaste, and ketchup are colloids, containing solid particles dispersed in a liquid.