The two-layered sac surrounding the heart is the pericardium.
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Answer:
Lactose intolerance is when your body can't break down or digest lactose. Lactose is a sugar found in milk and milk products. Lactose intolerance happens when your small intestine does not make enough of a digestive enzyme called lactase. Lactase breaks down the lactose in food so your body can absorb it.
Explanation:
<span>Pond organism is unicellular and crab is multi cellular.
The simplest level at which life exist is called the cell. Unicellular organism contain only one cell while multi cellular organisms contain more than one cell. Multi cellular organisms can be organized into various levels such as Cells>tissues> organs>organ systems> organism. Thus pond organism is unicellular under microscope and crab is multi cellular.</span>
Answer:
H20 and light ( last choice)
Answer:
Atoms are so small that it is difficult to believe that all matter is made from atoms—but it is. The concept that atoms play a fundamental role in chemistry is formalized by the modern atomic theory, first stated by John Dalton, an English scientist, in 1808.
Explanation: