1. B
2. B
3. C
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Answer:
keystone species
Explanation:
Keystone species are indispensable species that are essential to the maintaining of the balance of an ecosystem, and also play a major role in the way species in the ecosystem interrelate. The absence or removal of a keystone species from a habitat or ecosystem would lead to the disruption and imbalance of the ecosystem, and as such lead to the extinction of other species.
An example of a keystone species is the bee. Bees are very important in pollination of flowering plants and also ensure their survival. This plants serve as home to various insects that are source of food to birds. The removal of bees from this ecosystem would affect the ecological balance of this ecosystem.
Answer:
B) As seen from Earth, the Sun is the brightest star on the chart, and Barnard's Star is the dimmest
Explanation:
Among the given choices:
A) Of the stars listed, Proxima Centauri and Barnard's Star appear red because they burn the hottest.
This is not the correct answer because temperature of Barnard's star is 5000° F which is lowest in the data.
C) Small dwarf stars, like Proxima Centauri and Barnard's Star, do not burn as hot as medium dwarfs.
Proxima centauri being a small dwarf has a higher temperature than sun which is a medium dwarf.This shows that small dwarfs can burn hotter than medium dwarfs. So this option is not suitable.
D) Proxima Centauri and Barnard's Star are the closest because they are classified as "small dwarfs."
This is not correct choice because the data clearly states they are at greater distance.
So ,the correct choice is:
B) As seen from Earth, the Sun is the brightest star on the chart, and Barnard's Star is the dimmest.
Because: Sun is closest to the Earth and thus will appear the brightest as maximum light from it Reaches the Earth. Barnard's star is Farthest so less light reaches the Earth from it and it appears the dimmest.
Crayfish only swim backwards. Otherwise, the walk forwards
Answer:
The slc7a9 (Solute Carrier Family 7 Member 9) gene encodes for a protein that plays a critical role in the transport of cysteine in the kidneys, thereby a mutation in this gene may lead to health problems related to the urinary system. On the other hand, the SLC3A1 gene encodes a protein subunit which is required to form a transporter complex that is not involved in the transport of cysteine.