it is accepted that cells contain DNA in chromosomes and RNA in the nucleus and cytoplasm, but only in the modern cell theory. the classical cell theory does not include this. but using either classical or modern theory, it is false that all cells have DNA surrounded by a nucleus.

Robert Hooke

These findings led to the formation of the modern cell theory, which has three main additions: first, that DNA is passed between cells during cell division; second, that the cells of all organisms within a similar species are mostly the same, both structurally and chemically; and finally, that energy flow occurs within …

The Cell Theory Is a Unifying Principle of Biology The cell theory states that all biological organisms are composed of cells; cells are the unit of life and all life come from preexisting life. The cell theory is so established today that it forms one of the unifying principles of biology.

Knowing that all living things are made up of cells allows us to understand how organisms are created, grow, and die. That information helps us understand how new life is created, why organisms take the form they do, how cancer spreads, how diseases can be managed, and more.

The cell is the smallest unit of life because it is the most fundamental building block of every living organism.

The biological levels of organization of living things arranged from the simplest to most complex are: organelle, cells, tissues, organs, organ systems, organisms, populations, communities, ecosystem, and biosphere.

They are organized from smallest to largest; organism, population, community, ecosystem.

For example, the respiratory system and the circulatory system work closely together to deliver oxygen to cells and to get rid of the carbon dioxide the cells produce. The circulatory system picks up oxygen in the lungs and drops it off in the tissues, then performs the reverse service for carbon dioxide.

A tissue is a group of similar cells that work together to carry out a particular function. A group of differentiated cells forms a tissue. A tissue is a group of similar cells that work together to do a particular job. For example, most animals have muscle tissues, which are made up of muscle cells.

Describe three body processes or functions that all humans have in common. All humans are able to digest food for nutrients and energy (Digestive System), breathe to get oxygen (Respiratory System), and pee to get rid of wastes (Urinary System).

Similarly, the cardiovascular, integumentary (skin and associated structures), respiratory, and muscular systems work together to help the body maintain a stable internal temperature.

The circulatory and respiratory systems work together to circulate blood and oxygen throughout the body. Air moves in and out of the lungs through the trachea, bronchi, and bronchioles. Blood moves in and out of the lungs through the pulmonary arteries and veins that connect to the heart.

femur

The circulatory system is made up of blood vessels that carry blood away from and towards the heart. Arteries carry blood away from the heart and veins carry blood back to the heart. The circulatory system carries oxygen, nutrients, and hormones to cells, and removes waste products, like carbon dioxide.