STD 11 - 10. Cell cycle and cell division — BIOLOGY STD 11 Science — Question

$(a)$ Contraction of diaphragm

$(b)$ Contraction of external inter-costal muscles

$(c)$ Pulmonary volume decreases

$(d)$ Intra pulmonary pressure increases

$A$. Presence of a mid-dorsal, solid and double nerve cord.

$B$. Presence of closed circulatory system.

$C$. Presence of paired pharyngeal gill slits.

$D$. Presence of dorsal heart

$E$. Triploblastic pseudocoelomate animals.

Choose the correct answer from the options given below:

$(i)$ The shape of the cells may vary with the function they perform.

$(ii)$ Human $RBC$ is about $7.0\; mm$ in diameter.

$(iii)$ Cytoplasm is the main area of cellular activities.

$(iv)$ Various chemical reactions occur in cytoplasm to keep the cell in the living state.