Which are sources of adult stem cells? check all that apply. 1. bone marrow 2. amniotic fluid 3. brain  4. gametes 5. liver 6. embryo

The correct answer is -

1. bone marrow

3. brain

5. liver.

Stem cells are the undifferented cells (that is without having a specific function) of the body that are present in multicellular organisms in their adult as well as their embryonic stage.

They are capable of producing specialised cells (such as blood cells, liver cells, muscle cells etc) through a process called differentiation.

In adult stage, they are present in various body organs and tissues such as bone marrow, brain, skeletal muscles, testes, ovaries, blood vessels, liver etc.

Thus, option 1), 3), and 5) are the right answers.

what statement best describes the difference between the sympathetic and parasympathetic nervous systems?

the sympathetic nervous system prepares the body for intense physical activity and is often referred to as the fight-or-flight response. the parasympathetic nervous system has almost the exact opposite effect and relaxes the body and inhibits or slows many high energy functions.

c. earths continental crust is thicker than its lithosphere.

because, the lithosphere is the outermost layer of the earth/ 100 km thick and is defined by its machanical properties.the lithosphere contains oceanic and continental crust that varies in age and thickness across locations and geologic time. the lithosphere is the coolest layer of the earth in terms of temperature. the term lithosphere should not be confused with the use of "geosphere" which is used to indicate all of earth systems, including the atmosphere, hydrosphere   and biosphere. the surface of the earth can be divided into the continental crust and the oceanic crust.   the continental crust is made mostly of granite while the oceanic crust is made of basalt. the average thickness of the continental crust is 25 miles and the average thickness of the oceanic crust is 5 miles.   three types of rock, igneous, sedimentary, and metamorphic, make up the surface of the earth. that's why 3 option is preferable.