A) A flap in the heart located between each atrium and ventricle.
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<u>Answer:</u>
Mitochondria, the organelles involved in cellular respiration, can also generate chemicals called reactive oxygen species (ROSs). ROSs can damage mitochondria. Damaged mitochondria generate more ROSs than healthy mitochondria. This is an example of a positive feedback mechanism
The reactive oxygen species that are given out by the mitochondria during cellular respiration are the major cause of aging. Though this has a lot of negative effects but this also has a small amount of positive effects such as the start of angiogenesis or cell proliferation.
Answer:
it is D
What global climatic change gave gymnosperms an advantage over ferns?
A) Increased fluctuations in global climate
B) the climate becoming hotter and wetter
C) the climate becoming cooler and drier
D) the climate becoming hotter and drier
Answer:
Water is a covalent compound.
Explanation:
covalent compounds are individual molecules characterized by the sharing of electrons between two or more atoms. Two atoms with similar electronegativity will not exchange an electron from their outermost shell; the atoms instead share electrons so that their valence electron shell is filled.
Example:
Examples of compounds that contain only covalent bonds are methane (CH4), carbon monoxide (CO), Water (H2O) and iodine monobromide (IBr).
Properties:
1. At room temperature and normal atmospheric pressure, covalent compounds may exist as a solid, a liquid, or a gas.
2. Covalent compounds do not exhibit any electrical conductivity, either in pure form or when dissolved in water.
3. Covalent compounds have lower melting and boiling points.
