A solid minute object that is said to come together for the formation of the planet and are believed to produce cosmic dust are called planetesimal.
The options that best describes the planetesimals are:
- Option A. They are the origins of planets.
- Option B. They formed from gas and dust.
- Option D. They are believed to have developed in debris disks.
The descriptions can be explained as:
- It is believed that planets formation occurred through planetesimals. The formation happened from gas, dust particles and debris.
- By the process of accretion, the discs coalesced and became bigger and solid over time. This bigger mass started attracting other matters towards each other because of gravitational force.
- This pull resulted in either breaking or creation a bigger mass of pieces known as planetesimals. The collision continued to become bigger and solid planets we know today.
Therefore, options A, B and D are correct.
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Answer:
How do organisms interact with the living and non-living elements of their environments?
The interaction of living organisms with non-living organisms within an environment is called an ecosystem. Every living organism must interact with non-living organism in order to maintain a balanced ecosystem
Explanation:
Mussels are molluscans and are freshwater animals. The change in the environment led to new traits of mussels, it underwent natural selection and the thick shells have high chances of survival.
<h3>What is natural selection?</h3>
Natural selection is a process of nature that eliminates the organism with less survival and unfit traits while selecting the organisms with better traits of survival in the altered conditions.
The arrival or the introduction of the crabs in the environment altered the previous habitat of the mussels and led to the adaptation of the better trait quality in the mussel species.
The trait of the thick shells underwent natural selection as they were favoured for the changed conditions. The mussel having thick shells have high chances of survival over thin-shelled mussels as the crab will find it hard to attack the thick-shelled mussels.
Therefore, option A. change in environment, option B. natural selection and option E. chances of survival are the correct statements.
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Crossing over<span> occurs </span>between<span> prophase 1 and metaphase 1 and is the process where </span>homologous chromosomes<span> pair up with each other and </span>exchange<span> different segments of their genetic material to form recombinant </span>chromosomes<span>. It can also happen </span>during<span> mitotic division, which may </span>result<span> in loss of heterozygosity. </span>
Answer:
C. A gen, if present in a pair of alleles, is always expressed
Explanation: