Answer: The solid is a mixture
Explanation:
Here's the complete question:
If a solid contains some particles that melt at 50°C and other particles that melt at 110°C, what must be true about the solid?
A. The solid is an element.
B. The solid is a mixture.
C. The solid is a pure substance.
D. The solid has three boiling points.
It should be noted that an element consist of an atom but in this scenario, there are different particles that also have different melting points. Therefore, it's not an element, but rather a mixture.
Also, the solid in this case is not a pure substance and doesn't have three boiling points.
Therefore, the correct option is B.
Answer:
The correct answer is option (d)-"All of these are found in the fossil record and have been used by scientists to understand human evolution".
Explanation:
There is plenty of evidence that supports the proposal of how humans has evolved during past times. The fossil records that scientists has used understand human evolutionary patterns include the following. Ardipithecus ramidus bones that revealed advances in upright walking, even tough they had a small brain that measured between 300 and 350 cm3. Australopithecus lack of an opposable big toe suggest that they lived on the ground instead of in trees. Homo erectus was the first species to use and control fire, as suggested by evidence of microscopic traces of wood ash.
Cells prevent mutations during DNA replication by using their mechanisms which are mismatch repair, direct repair, base excision repair, and nucleotide excision repair.
Answer:
protein and energy
Explanation:
if you look close at the wall of a plant it has cellulose and hemicellulose.
Answer:
The presence of cholesterol in the plasma membranes of some animal cells <u>enables the membranes to stay fluid when cell temperature drops</u>.
Explanation:
Cholesterol is an essential lipid in the basic structure of cell membranes. The membranes must have a fluid structure so that the proteins integrated in them can move ''horizontally'' to interact with their ligands and with other proteins. With excess saturated fat the membranes become rigid, but only with the necessary unsaturated fat the membranes are extremely fluid, and very sensitive to changes in temperature. Cholesterol stabilizes the structure of the membranes; preventing the collapse and crystallization between lipid chains that would lead to loss of fluidity and excessive rigidity in the membrane. By decreasing the temperature; as temperatures drop, fluidity decreases, an effect that partially counteracts the presence of cholesterol.
