As microscope technology improved over time, the magnification became advanced enough to discover cells in the 17th century. This discovery is largely attributed to Robert Hooke, and began the scientific study of cells, also known as cell biology. Over a century later, debate continued among scientists about how cells began. Most of these debates involved the nature of cell reproduction, and the idea of cells as a fundamental unit of life. Cell theory was eventually formulated in 1839.


The three tenets to the cell theory are as described below:

1. All living organisms are composed of one or more cells.

2. The cell is the basic unit of structure and organization in organisms.

3. Cells arise from pre-existing cells.


Anton van Leeuwenhoek is a scientist who saw cells soon after Hooke did. He made use of a microscope containing improved lenses that could magnify objects almost 30ox. Under these microscopes, Leeuwenhoek found moving objects that he named “animalcules,” which included protozoa and other unicellular organisms, like bacteria. He was also able to observe red blood cells and sperm cells. Leeuwenhoek's research can be used to support which of the tenets of cell theory?


A.) some cells emerge spontaneously.

B.) the cell is the basic unit of structure and organization in organisms.

C.) cells arise from pre-existing cells.

D.) all living and non-living items are made of cells.

Answer: The correct answer will be option-B.

Explanation:

Many of the foods you eat contain large molecules called polymers that are broken down into their building blocks or monomers that can be used for processes such as cellular respiration. Which of these correctly pairs a macromolecule and its monomer? Select ALL that apply.

A.) carbohydrates: monosaccharides
B.) lipids: fatty acids and glycerol
C.) carbohydrates: glycosides
D.) proteins: amino acids
E.) proteins: peptides

Заполни пропуски в предложениях.
Человек в отличие от животных обладает ______, способен к ______, может действовать ______, имеет хорошо развитый ______, создает ______.

Fill in the gaps in the sentences.
A person, unlike animals, has ______, is capable of ______, can act ______, has a well-developed ______, creates ______.

Part 1:
Some agencies in the ____are turning to unconventional methods of communication.
A) United States
B) United Nation
C) United KIndom
D) United Arab Emirates

Lots of things require balance: riding a bike, walking a balance beam, jumping rope. Losing balance can cause us to get hurt. The same is true for living things. Plants and animals must maintain an internal balance to stay healthy. Living things have internal communication systems that help to keep things in homeostasis or balance. A stimulus is any change in an organism’s environment that causes the organism to react. The change can be internal or external. For example, when you get hot, you move to the shade. The heat is an external stimulus and moving to the response is the response you make to cool off or come back to homeostasis. If you get hungry, you eat a snack. The hunger is an internal stimulus. Eating a snack is your response.

Which of these is a response to an external stimuli? Select ALL that apply.


A.) hibernation
B.) phototropism
C.) wilting
D.) thirst
E.) dormancy

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