?

N.c Sai Sarani answered  •  3 hours ago
Most sources state that there are over 640 named skeletal muscles in the human body, although some figures go up to as many as 840. The dissension comes from those that count the muscles within a complex muscle.

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Nucleotide arrangement in DNA can be seen by
  • a)
    X-ray crystallography
  • b)
    electron microscope
  • c)
    ultracentrifuge
  • d)
    light microscope
Correct answer is option 'A'. Can you explain this answer?

Akanksha Mahalle answered  •  3 hours ago
Nucleotide arrangement in DNA can be seen by X-ray Crystallography. X-ray crystallography is used to determine 3D structures of macromolecules like proteins, nucleotides, etc. The basic principle of this techniques is that the wavelength of x-rays depends on the distance between the atoms of the structures which makes it useful for determining their arrangement.

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Movement of ions or molecules in a direction opposite to that of prevailing electrochemical gradient is known as
  • a)
    diffusion
  • b)
    active transport
  • c)
    pinocytosis
  • d)
    brownian movement
Correct answer is option 'B'. Can you explain this answer?

Akanksha Mahalle answered  •  3 hours ago
Active Transport is defined as a process that involves the movement of molecules from a region of lower concentration to a region of higher concentration against a gradient or an obstacle with the use of external energy.”During the process of active transport, a protein pump makes use of stored energy in the form of ATP, to move molecules .The process of active is which uses an external energy ATP... more

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The new varieties of plants are produced by
  • a)
    selection and hybridisation
  • b)
    mutation and selection
  • c)
    introduction and mutation
  • d)
    selection and introduction
Correct answer is option 'A'. Can you explain this answer?

Akanksha Mahalle answered  •  3 hours ago
The new plant varieties are produced by selection and hybridization. Selection is a non-random process which leads to individuals of different genotypes being represented unequally in their progeny in later generations of a population of self propagating units. Selection can be natural or artificial.As a part of agriculture, man started rearing plants and animals to meet his requirements. This is ... more

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Plant body is gametophytic and bears haploid gametes in
  • a)
    Riccia
  • b)
    Lycopodium
  • c)
    Equisetum
  • d)
    Pinus
Correct answer is option 'A'. Can you explain this answer?

Akanksha Mahalle answered  •  3 hours ago
The plant body of Riccia is gametophytic and gametophytes are fleshy, prostrate and dichotomously branched. Repeated dichotomy results into a typically rosette like appearance ..Riccia thallus grow in large number in close association, covering the surface like a mat. They are relatively poorly adapted to life on land. So they are mainly confined to damp and shady places. The species of Riccia are... more

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Potometer, works on the principle of
  • a)
    amount of water absorbed equals to the amount transpired
  • b)
    osmotic pressure
  • c)
    root pressure
  • d)
    potential difference between the tip of the tube and that of the plant
Correct answer is option 'A'. Can you explain this answer?

Akanksha Mahalle answered  •  3 hours ago
A potometer can be used to measure the rate of transpiration that's proportional to water uptake. Transpiration cannot be measured directly as some of the water will be used in photosynthesis..A potometer or transpirometer is a tool used to measure the rate of water loss from the leaves of the plant. Potometer measures the rate of transpiration on the basis of the equal amount of water absorbed a... more

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Rate of heart beat is determined by 1).purkinjee fibres. 2).papillary muscles. 3).AV node. 4).SA node.?

Akanksha Mahalle answered  •  4 hours ago
The sino atrial node (SA) node, present in upper posterior wall of right atrium, serves as pacemaker as it's rate of impulse generation is hightest (0.85/second) and determines the rate and rhythm of heartbeat. Atrio Ventricular Node (AVN) is a nodal tissue that regulates the heart beat and is present in base of right atrium adjacent to interatrial septum. It produces impulse at rate of 0.45/secon... more

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Papillary muscles are found in :-
  • a)
    Haemocoel of cockroach
  • b)
    Auricles of heart
  • c)
    Ventricles of heart
  • d)
    Arm
Correct answer is option 'C'. Can you explain this answer?

N.c Sai Sarani answered  •  4 hours ago
C is the answer .The heart's ventricles, the two bottom chambers, contain muscles known as papillary muscles. These muscles attach to the leaflets of the tricuspid valve and bicuspid (mitral) valve via string-like tendons called the chordae tendineae

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