A. It forms a part of the upper atmosphere known as the ozone layer.
Cyclins
are the chemicals that regulate the cell cycle. Cyclins work by regulating the timing
of the cell cycle in eukaryotic cell. Cyclins activates cyclin dependent
kinases (CDKs) (an enzyme that works by adding <span>negatively charged phosphate groups to other
molecules in a process called phosphorylation) by binding to it to form a cyclin-Cdk
complex. This complex then functions by acting as a signal to the cell to move
to the next cell cycle phase. At the end of the event, the cyclin is degraded, Cdk
is deactivated, therefore signaling exit from a specific phase.</span>
Soaring is a science when birds remain airborne and moving without flapping their wings. They are maintaining thrust and gliding downward but staying aloft
<h3 /><h3>Further explanation</h3>
Soaring birds is where the birds can maintain flight without wing flapping, because they using rising air currents. Many gliding birds are able to lock their extended wings by means of a specialized tendon. Some land birds such as vultures and certain hawks, sustain flight for long periods without flapping their wings.
For example soaring California Condor spreads its primary feathers so that each acts as a small, high-aspect-ratio wing. This reduces turbulence at the wingtips and helping the condor to stay aloft circling slowly in thermals.
Vultures have a low aspect ratio (ratio of length to width of the wing) which generally produce a lot of drag. Vultures overcome the problem of by flying with their primary feathers extended, creating slots between them. Each primary serves as an individual high-aspect-ratio wing. This high-aspect-ratio reducing wingtip turbulence and lowering the stalling speed of the wings. This helps vultures to circle in thermals, maintaining thrust by gliding downward, but staying aloft by sinking at a rate slower than the hot air rising.
<h3 /><h3>Learn more</h3>
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<h3>Answer details</h3>
Grade: 9
Subject: biology
Chapter: animals
Keywords: birds
Answer:Eukaryotes only (A) and (D), bacteria only (E) both (B) and (C).
Explanation:
(A) Only eukaryotes have a nucleus.
(B) Both replicate the DNA before performing cell division, so each cell keeps a copy.
(C) This structural feature is called centromere in eukaryotes and in bacteria this role is played by the origin of replication.
(D) Centromeres are eukaryotes exclusive.
(E) Only bacteria have a replication origin.