Which planet is considered as the Earth's twin planet due to similarity in…

Concept

A planet is called another planet’s "twin" on the strength of its bulk physical parameters — equatorial diameter, mass, volume and mean density. The label is earned when those quantities are nearly equal, that is, when the ratio of one body’s value to the other’s approaches 1. Orbital neighbourhood, surface temperature and atmospheric composition are deliberately outside this criterion.

Application

Take Earth as the reference — equatorial diameter 12,756 km, mass 1 Earth mass, mean density 5.51 g/cm3 — and compare each planet named in the item:

Reading the ratio columns, only one body sits close to 1 on both diameter and mass: Venus, at 0.95 and 0.815. Mars is about half Earth’s width and a ninth of its mass; Jupiter is eleven times wider and 318 times heavier, and its low 1.33 g/cm3 density marks it as a gas giant rather than a rocky body at all.

Cross-check and contrast

• Density confirms the match, not just size: 5.24 against Earth’s 5.51 g/cm3 means Venus has the same iron-core-plus-silicate-mantle build, so the resemblance is structural and not a coincidence of diameter.

• The twin label is strictly about bulk size, mass and composition. Venus’s surface sits near 465 °C under a 92-bar carbon-dioxide atmosphere, so in climate and habitability it is nothing like Earth — a common trap in this question.

• Exactly one of the named planets clears the near-equality test, so neither the "more than one" nor the "none" combination choice holds.

Therefore the planet regarded as Earth’s twin, on grounds of similar shape and size, is Venus.