It is B since they are traveling at the same speed one is positive so the other had to be negative hope this helps;)))))
S orbital.
Group 1 elements have a general configuration 
, where n represents the highest occupied Principal Energy Level. For example, Lithium has the valence configuration 
whereas Cesium has 
. Both of them belong to Group 1 of Periodic Table.
Group 2 elements have a general configuration of 
. For example, Magnesium has 
as its outer shell configuration while Strontium has the same as 
.
We see that in both the cases, the outermost S orbital is being filled.
Answer:
very small solid particles called interstellar dust.
Explanation:
In the space between the stars there is gas and dust, which represent at least 20% of the mass of our galaxy. In the Milky Way it is considered that there is a gas density of approximately 0.2 to 0.5 atoms / cm3 in the surroundings of the Sun; with respect to the dust an average of 1 g / cm3 is estimated.
Gas is about atoms and molecules, mainly hydrogen; In order of abundance, helium, carbon, oxygen, nitrogen and iron follow. On the other hand, the dust is tiny particles, generally smaller than 10 microns; the dust does not shine and therefore it is only distinguished when it is projected on bright regions (nebulae or clusters).
Interstellar matter is mainly concentrated towards the plane of the galaxy, in the strip corresponding to the Milky Way; there you can see bright nebulas of diffuse character called nebulas. These nebulae are classified according to three types: (a) bright or emission nebulae, (b) reflection nebulae and (c) planetary nebulae.
Hydrogen appears both ionized and neutral; The bright nebulae are composed of ionized hydrogen and other ionized elements. Non-ionized (neutral) hydrogen is found in the spiral arms of the Milky Way and can be detected through radio waves.
The most massivest stars end their lives as black holes. <em>(D)</em>
Answer:
the changes in waves
Explanation:
the moon has its own gravitational pull thus making waves and the rising tides
